Acyl hydrazone derivative compounds for treating disease

ABSTRACT

The present invention relates to compounds that have zinc and/or iron ionophore activity and their use in treating diseases that are modulated by reducing zinc and/or iron. In particular embodiments, the compounds are compounds of formula (I):

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Australian Patent Application No. 2020903058, filed Aug. 27, 2020, the entire contents of which is hereby fully incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to compounds that have zinc and/or iron ionophore activity and their use in treating diseases that are modulated by reducing zinc and/or iron.

BACKGROUND OF THE INVENTION

Zinc and iron are micronutrients involved in a number of biological processes including immune response, metabolism, nucleic acid synthesis and repair, apoptosis and redox homeostasis and can be important in host-pathogen interactions.

Zinc has been implicated in processes involved in diseases such as cancer and neurological diseases and has been shown to have antiviral, antibiotic and anti-infective activities.

Iron has been implicated in processes involved in neurodegenerative disorders and disorders associated with iron overload.

The ability to chelate zinc and/or iron and transport zinc and/or iron, for example, from the extracellular environment to the intracellular environment has utility in diverse disease processes. There is a need for further zinc and iron ionophores that may be useful in treating or managing disease processes.

SUMMARY OF THE INVENTION

Described herein are compounds of formula (I):

wherein X is O or S;

R₁ is selected from:

Y₁ is CR₈ or N;

Y₂ is CR₈ or N;

provided that both Y₁ and Y₂ are not N;

Y₃ is C(R₈)₂, NR₉ or S;

Y₄ is CR₈ or N;

provided that Y₃ is not C(R₈)₂ when Y₄ is CR₈;

R₆ and R₇ are independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, CN, CO₂R₉ and N(R₉)₂; or

R₆ and R₇ taken together with the atoms to which they are attached form an optionally substituted 6 membered aryl or heteroaryl ring;

each R₈ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, (C(R₁₀)₂)_(m)CO₂R₉ and (C(R₁₀)₂)_(m)N(R₉)₂;

each R₉ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl;

R₂ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, C₃₋₈ cycloalkyl and

R₁ and R₂ taken together for a 5, 6 or 7 membered cycloalkyl or heterocycloalkyl ring fused with a six-membered nitrogen-containing heteroaryl ring, wherein the cycloalkyl, heterocycloalkyl or heteroaryl ring may be optionally substituted,

R₃ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and (C(R₁₀)₂)_(m)CO₂R₉;

R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl; and R₅ is hydrogen, (C(R₁₀)₂)_(m)aryl or (C(R₁₀)₂)_(m)heteroaryl wherein aryl and heteroaryl are optionally substituted; or

R_(4a) is CN and R₄ and R₅ taken together form:

where R₁₄ is hydrogen, (C(R₁₀)₂)_(m)aryl or (C(R₁₀)₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; or

R_(4a) is absent and R₄ and R₅ taken together form an optionally substituted aryl or optionally substituted heteroaryl group;

each R₁₀ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, CN, halo and N(R₉)₂;

m is 0 or an integer of 1 to 6;

or a pharmaceutically acceptable salt thereof.

Also described herein are compounds of formula (Ia):

wherein X is O or S;

R₁ is selected from:

Y₁ is CR₈;

Y₂ is CR₈ or N;

Y₃ is C(R₈)₂, NR₉ or S;

Y₄ is CR₈ or N;

provided that Y₃ is C(R₈)₂ then Y₄ is not CR₈;

R₆ and R₇ are independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, CN, C₀₂R₉ and N(R₉)₂; or

R₆ and R₇ taken together with the atoms to which they are attached form an unsubstituted 6 membered aryl or heteroaryl ring;

each R₈ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, (CH₂)_(m)CO₂R₉ and (CH₂)_(m)N(R₉)₂;

each R₉ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl;

R₂ is selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, C₃₋₈ cycloalkyl and

R₁ and R₂ taken together for a 5, 6 or 7 membered cycloalkyl ring fused with a six membered nitrogen-containing heteroaryl ring, wherein the cycloalkyl or heteroaryl ring may be optionally substituted,

R₃ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C(R₁₀)₂)_(m)CO₂R₉;

R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂-6alkynyl and C₁₋₆haloalkyl; and R₅ is (C(R₁₀)₂)_(m)aryl or (C(R₁₀)₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; or

R_(4a) is CN and R₄ and R₅ taken together form:

where R₁₄ is hydrogen, (C(R₁₀)₂)_(m)aryl or (C(R₁₀)₂)_(m)heteroaryl wherein aryl and heteroaryl are optionally substituted; or

R_(4a) is absent and R₄ and R₅ taken together form an optionally substituted aryl or optionally substituted heteroaryl group;

each R₁₀ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, CN, halo and N(R₉)₂;

m is 0 or an integer of 1 to 6;

or a pharmaceutically acceptable salt thereof.

Also described herein are compounds of formula (Ib):

wherein X is O;

R₁ is selected from:

R₆ and R₇ are independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, CN, C₀₂R₉ and N(R₉)₂; or

R₆ and R₇ taken together with the atoms to which they are attached form an optionally substituted 6-membered aryl or heteroaryl ring;

-   -   each R₈ is independently selected from hydrogen, C₁₋₆alkyl,         C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl,         C₁₋₆haloalkoxy, halo, (C(R₁₀)₂)_(m)CO₂R₉ and         (C(R₁₀)₂)_(m)N(R₉)₂;

each R₉ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl;

R₂ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, C₃₋₈ cycloalkyl and

R₁ and R₂ taken together form

wherein V is CH, O or S and Rn and R₁₂ are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, halo, C₁₋₆haloalkyl, (CH₂)_(m)C₃₋₈cycloalkyl, (CH₂)_(m)aryl, (CH₂)_(m)heterocyclyl, (CH₂)_(m)heteroaryl and COR₁₃ where R₁₃ is selected from OH, OC₁₋₆alkyl, OC₂₋₆alkenyl, OC₂₋₆alkynyl and N(R₉)₂, wherein the cycloalkyl, heterocycloalkyl or heteroaryl ring of the bicyclic structure formed from R₁ and R₂ may be optionally substituted, or

R₁ and R₂ are both:

R₃ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and (C(R₁₀)₂)_(m)CO₂R₉; R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl; and R₅ is hydrogen, (C(R₁₀)₂)_(m)aryl, (C(R₁₀)₂)_(m)heteroaryl, O(C(R₁₀)₂)_(m)aryl or O(C(R₁₀)₂)_(m)heteroaryl wherein the aryl and heteroaryl are optionally substituted; or

R_(4a) is CN and R₄ and R₅ are each hydrogen or are taken together form:

where R₁₄ is hydrogen, (C(R₁₀)₂)_(m)aryl or (C(R₁₀)₂)_(m)heteroaryl wherein the aryl and heteroaryl are optionally substituted; or

R_(4a) is absent and R₄ and R₅ taken together form an optionally substituted aryl or optionally substituted heteroaryl group;

each R₁₀ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, CN, halo and N(R₉)₂;

m is 0 or an integer of 1 to 6;

or a pharmaceutically acceptable salt thereof.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, preferred methods and materials are described. For the purposes of the present invention, the following terms are defined below.

The articles “a” and “an” are used herein to refer to one or to more than one (i.e. to at least one) of the grammatical object of the article. By way of example, “an element” means one element or more than one element.

As used herein, the term “about” refers to a quantity, level, value, dimension, size, or amount that varies by as much as 15% or 10% to a reference quantity, level, value, dimension, size, or amount.

Throughout this specification, unless the context requires otherwise, the words “comprise”, “comprises” and “comprising” will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements.

As used herein, the term “alkyl” refers to a straight chain or branched saturated hydrocarbon group having 1 to 10 carbon atoms. Where appropriate, the alkyl group may have a specified number of carbon atoms, for example, C₁₋₆alkyl which includes alkyl groups having 1, 2, 3, 4, 5 or 6 carbon atoms in a linear or branched arrangement. Examples of suitable alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl, 2-methylbutyl, 3-methylbutyl, 4-methylbutyl, n-hexyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 5-methylpentyl, 2-ethylbutyl, 3-ethylbutyl, heptyl, octyl, nonyl and decyl.

The term “haloalkyl” as used herein refers to an alkyl group as defined above where one or more hydrogen atoms have been replaced with a halogen atom and includes perhalogenated alkyl groups. Examples of suitable haloalkyl groups include fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl, chlorofluoromethyl, difluorochloromethyl, dichlorofluoromethyl, bromomethyl, iodomethyl, 1-fluoroethyl, 2-fluoroethyl, 1-chloroethyl, 2-chloroethyl, 1-bromoethyl, 2-bromoethyl, 1-iodoethyl, 2-iodoethyl, 1-fluoropropyl, 2-fluoropropyl, 3-fluoropropyl, 1-chloropropyl, 2-chloropropyl, 3-chloropropyl, and the like.

As used herein, the term “alkenyl” refers to a straight-chain or branched hydrocarbon group having one or more double bonds between carbon atoms and having 2 to 10 carbon atoms. Where appropriate, the alkenyl group may have a specified number of carbon atoms. For example, C₂₋₆ as in “C₂₋₆alkenyl” includes groups having 2, 3, 4, 5 or 6 carbon atoms in a linear or branched arrangement. Examples of suitable alkenyl groups include, but are not limited to, ethenyl, propenyl, isopropenyl, butenyl, butadienyl, pentenyl, pentadienyl, hexenyl, hexadienyl, heptenyl, octenyl, nonenyl and decenyl.

As used herein, the term “alkynyl” refers to a straight-chain or branched hydrocarbon group having one or more triple bonds and having 2 to 10 carbon atoms. Where appropriate, the alkynyl group may have a specified number of carbon atoms. For example, C₂₋₆ as in “C₂₋₆alkynyl” includes groups having 2, 3, 4, 5 or 6 carbon atoms in a linear or branched arrangement. Examples of suitable alkynyl groups include, but are not limited to ethynyl, propynyl, butynyl, pentynyl and hexynyl.

As used herein, the term “cycloalkyl” refers to a saturated cyclic hydrocarbon. The cycloalkyl ring may include a specified number of carbon atoms. For example, a 3 to 10 membered cycloalkyl group includes 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. Examples of suitable cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl and cyclodecyl.

As used herein, the term “aryl” is intended to mean any stable, monocyclic, bicyclic or tricyclic carbon ring system of up to 7 atoms in each ring, wherein at least one ring is aromatic. Examples of such aryl groups include, but are not limited to, phenyl, naphthyl, tetrahydronaphthyl, indanyl, fluorenyl, phenanthrenyl, biphenyl and binaphthyl.

As used herein, the term “halogen” or “halo” refers to fluorine (fluoro), chlorine (chloro), bromine (bromo) and iodine (iodo).

As used herein, the terms “alkoxy” and “haloalkyloxy” refer to alkyl and haloalkyl groups defined above respectively when attached to an oxygen. Suitable examples include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, t-butoxy, n-pentoxy, 2-methylbutoxy, 3-methylbutoxy, 4-methylbutoxy, n-hexoxy, 2-methylpentxoy, 3-methylpentoxy, 4-methylpentoxy, 5-methylpentoxy, 2-ethylbutoxy, 3-ethylbutoxy, fluoromethoxy, difluoromethoxy, trifluoromethoxy, chloromethoxy, dichloromethoxy, trichloromethoxy, chlorofluoromethoxy, difluorochloromethoxy, dichlorofluoromethoxy, bromomethoxy, iodomethoxy, 1-fluoroethoxy, 2-fluoroethoxy, 1-chloroethoxy, 2-chloroethoxy, 1-bromoethoxy, 2-bromoethoxy, 1-iodoethoxy, 2-iodoethoxy, 1-fluoropropoxy, 2-fluoropropoxy, 3-fluoropropoxy, 1-chloropropoxy, 2-chloropropoxy and 3-chloropropyl.

The term “heterocyclic” or “heterocyclyl” as used herein, refers to a cyclic hydrocarbon, such as a cycloalkyl group defined above, in which one to four carbon atoms have been replaced by heteroatoms independently selected from the group consisting of N, N(R), S, S(O), S(O)₂ and O. A heterocyclic ring may be saturated or unsaturated but not aromatic. Examples of suitable heterocyclyl groups include azetidine, tetrahydrofuranyl, tetrahydrothiophenyl, pyrrolidinyl, 2-oxopyrrolidinyl, pyrrolinyl, pyranyl, dioxolanyl, piperidinyl, 2-oxopiperidinyl, pyrazolinyl, imidazolinyl, thiazolinyl, dithiolyl, oxathiolyl, dioxanyl, dioxinyl, dioxazolyl, oxathiozolyl, oxazolonyl, piperazinyl, morpholino, thiomorpholinyl, 3-oxomorpholinyl, dithianyl, trithianyl and oxazinyl.

The term “heteroaryl” as used herein, represents a stable monocyclic, bicyclic or tricyclic ring of up to 7 atoms in each ring, wherein at least one ring is aromatic and at least one ring contains from 1 to 4 heteroatoms selected from the group consisting of O, N and S. Heteroaryl groups within the scope of this definition include, but are not limited to, acridinyl, carbazolyl, cinnolinyl, quinoxalinyl, quinazolinyl, pyrazolyl, indolyl, isoindolyl, 1H,3H-1-oxoisoindolyl, benzotriazolyl, furanyl, thienyl, thiophenyl, benzothienyl, 4H-thieno[3,2-c]chromene, benzofuranyl, benzodioxane, benzodioxin, quinolinyl, isoquinolinyl, oxazolyl, isoxazolyl, imidazolyl, pyrazinyl, pyridazinyl, pyridinyl, pyrimidinyl, pyrrolyl, tetrahydroquinolinyl, thiazolyl, isothiazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,4-oxadiazolyl, 1,2,4-thiadiazolyl, 1,2,3-thiadiazolyl, 1,3,5-triazinyl, 1,2,4-triazinyl, 1,2,4,5-tetrazinyl and tetrazolyl.

Each alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclyl and heteroaryl whether an individual entity or as part of a larger entity may be optionally substituted with one or more optional substituents selected from the group consisting of C₁₋₆alkyl, C₂₋₆alkenyl, C₃₋₆cycloalkyl, oxo (═O), —OH, —SH, C₁₋₆alkylO—, C₂₋₆alkenylO—, C₃₋₆cycloalkylO—, C₁₋₆alkylS—, C₂₋₆alkenylS—, C₃₋₆cycloalkylS—, —CO₂H, —CO₂C₁₋₆alkyl, —OC(═O)C₁₋₆alkyl, —NH₂, —NH(C₁₋₆alkyl), —N(C₁₋₆alkyl)₂, —NH(phenyl), —N(phenyl)₂, —C₁₋₆alkylNH₂, —C₁₋₆alkylNH(C₁₋₆alkyl), —C₁₋₆alkylN(C₁₋₆alkyl)₂, —C₁₋₆alkylNH(phenyl), —C₁₋₆alkylN(phenyl)₂, —OC₁₋₆alkylNH₂, —OC₁₋₆alkylNH(C₁₋₆alkyl), —OC₁₋₆alkylN(C₁₋₆alkyl)₂, —OC₁₋₆alkylNH(phenyl), —OC₁₋₆alkylN(phenyl)₂, —CN, —NO2, -halogen, —CF₃, —OCF₃, —SCF₃, —CHF₂, —OCHF₂, —SCHF₂, -phenyl, -heterocyclyl, -heteroaryl, —Oheteroaryl, —Oheterocyclyl, —Ophenyl, —OC₁₋₆alkylheteroaryl, —OC₁₋₆alkylheterocyclyl, —OC₁₋₆alkylphenyl, —C(═O)phenyl, —C(═O)C₁₋₆alkyl. Examples of suitable substituents include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, vinyl, methoxy, ethoxy, propoxy, isopropoxy, butoxy, methylthio, ethylthio, propylthio, isopropylthio, butylthio, hydroxy, oxo, hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, fluoro, chloro, bromo, iodo, cyano, nitro, —CO₂H, —CO₂CH₃, —OC(═O)CH₃, trifluoromethyl, trifluoromethoxy, trifluoromethylthio, difluoromethyl, difluoromethoxy, difluoromethylthio, morpholino, amino, methylamino, dimethylamino, ethylamino, diethylamino, aminoC₁₋₆alkyl, methylaminoC₁₋₆alkyl, dimethylaminoC₁₋₆alkyl, ethylaminoC₁₋₆alkyl, diethylaminoC₁₋₆alkyl, aminoC₁₋₆alkoxy, methylaminoC₁₋₆alkoxy, dimethylaminoC₁₋₆alkoxy, ethylaminoC₁₋₆alkoxy, diethylaminoC₁₋₆alkoxy, phenyl, phenoxy, phenylcarbonyl, benzyl, phenylethoxy, phenylmethoxy, phenylpropoxy, pyrrolidinylmethoxy, pyrrolidinylethoxy, pyrrolidinylpropoxy, pyridinylmethoxy, pyridinylethoxy, pyridinylpropoxy and acetyl.

The compounds of the invention may be in the form of pharmaceutically acceptable salts. It will be appreciated however that non-pharmaceutically acceptable salts also fall within the scope of the invention since these may be useful as intermediates in the preparation of pharmaceutically acceptable salts or may be useful during storage or transport. Suitable pharmaceutically acceptable salts include, but are not limited to, salts of pharmaceutically acceptable inorganic acids such as hydrochloric, sulphuric, phosphoric, nitric, carbonic, boric, sulfamic, and hydrobromic acids, or salts of pharmaceutically acceptable organic acids such as formic, acetic, propionic, butyric, tartaric, maleic, hydroxymaleic, fumaric, citric, lactic, mucic, malonic, malic (L), lactic (DL), mandelic (DL), gluconic, carbonic, benzoic, succinic, oxalic, phenylacetic, methanesulphonic, ethanesulphonic, toluenesulphonic, camphorsulphonic, benezenesulphonic, salicylic, cinnamic, cyclamic, sulphanilic, aspartic, glutamic, glutaric, galactaric, gentisic, hippuric, edetic, stearic, palmitic, oleic, lauric, pantothenic, tannic, ascorbic and valeric acids.

Base salts include, but are not limited to, those formed with pharmaceutically acceptable cations, such as sodium, potassium, lithium, calcium, magnesium, aluminium, zinc, lysine, histidine, meglumine, ammonium and alkylammonium.

Basic nitrogen-containing groups may be quaternized with such agents as lower alkyl halide, such as methyl, ethyl, propyl, and butyl chlorides, bromides and iodides; dialkyl sulfates like dimethyl and diethyl sulfate; and others.

The compounds of the invention may also be in the form of solvates, including hydrates. The term “solvate” is used herein to refer to a complex of variable stoichiometry formed by a solute (a compound of formula (I)) and a solvent. Such solvents should not interfere with the biological activity of the solute. Solvents that may be included in a solvate include, but are not limited to, water, ethanol, propanol, and acetic acid. Methods of solvation are generally known within the art.

The term “pro-drug” is used in its broadest sense and encompasses those derivatives that are converted in vivo to the compounds of formula (I). Such derivatives would readily occur to those skilled in the art and include, for example, compounds where a free hydroxy group is converted into an ester derivative or a ring nitrogen is converted to an N-oxide. Examples of ester derivatives include alkyl esters, phosphate esters and those formed from amino acids. Conventional procedures for the preparation of suitable prodrugs are described in text books such as “Design of Prodrugs” Ed. H. Bundgaard, Elsevier, 1985.

It will also be recognised that compounds of the invention may possess asymmetric centres and are therefore capable of existing in more than one stereoisomeric form. The invention thus also relates to compounds in substantially pure isomeric form at one or more asymmetric centres eg., greater than about 90% ee, such as about 95% or 97% ee or greater than 99% ee, as well as mixtures, including racemic mixtures, thereof. Such isomers may be prepared by asymmetric synthesis, for example using chiral intermediates, or by chiral resolution. The compounds of the invention may exist as geometric isomers. The invention also relates to compounds in substantially pure cis (Z) or trans (E) or mixtures thereof.

The compounds of the invention may also exist in the form of rotational isomers or conformers where there is restricted or hindered rotation about a single bond.

Any formula or structure given herein, including Formula (I) compounds are also intended to represent unlabelled forms as well as isotopically labelled forms of the compounds for use as medicaments or as a study tool. This may include metabolic studies, reaction kinetic studies, detection or imaging techniques, such as positron emission tomography (PET) or single-photon emission computed tomography (SPECT) including drug or substrate tissue distribution assays or in radioactive treatment of patients. Isotopically labelled compounds have structures depicted by the formulas given herein except that one or more atoms are replaced by an atom having a selected atomic mass or mass number. Examples of isotopes that can be incorporated into compounds of the disclosure include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, fluorine and chlorine, such as, but not limited to ²H (deuterium, D), ³H (tritium), ¹⁰B, ¹¹C, ¹³C, ¹⁴C, ¹⁵N, ¹⁸F, ³¹P, ³²P, ³⁵S, ³⁶Cl and ¹²⁵I. Various isotopically labelled compounds of the present disclosure, for example those into which radioactive isotopes such as ³H, ¹³C and ¹⁴C are incorporated. In addition to use as pharmaceutical treatments, such isotopically labelled compounds may be useful.

Compounds of the Invention

The present invention provides metal ion modulating compounds, particularly zinc and iron selective ionophores. Such ionophores may have one or more of the desirable properties of: orally deliverable; low liver extraction, non-toxicity and the ability to modulate metals, particularly zinc and iron in biological systems. Advantageous metal selectivity, affinity and kinetic stability of the complexes formed may also be provided by particular compounds.

Described herein are compounds of formula (I):

wherein X is O or S;

R₁ is selected from:

Y₁ is CR₈ or N;

Y₂ is CR₈ or N;

provided that both Y₁ and Y₂ are not N;

Y₃ is C(R₈)₂, NR₉ or S;

Y₄ is CR₈ or N;

provided that Y₃ is not C(R₈)₂ when Y₄ is CR₈;

R₆ and R₇ are independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, CN, CO₂R₉ and N(R₉)₂; or

R₆ and R₇ taken together with the atoms to which they are attached form an optionally substituted 6-membered aryl or heteroaryl ring;

each R₈ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, (C(R₁₀)₂)_(m)CO₂R₉ and (C(R₁₀)₂)_(m)N(R₉)₂;

each R₉ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl;

R₂ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, C₃₋₈ cycloalkyl and

or

R₁ and R₂ taken together for a 5, 6 or 7 membered cycloalkyl or heterocycloalkyl ring fused with a six membered nitrogen-containing heteroaryl ring, wherein the cycloalkyl, heterocycloalkyl or heteroaryl ring may be optionally substituted,

R₃ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and (C(R₁₀)₂)_(m)CO₂R₉;

R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl; and R₅ is hydrogen, (C(R₁₀)₂)_(m)aryl or (C(R₁₀)₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; or

R_(4a) is CN and R₄ and R₅ taken together form:

where R₁₄ is hydrogen, (C(R₁₀)₂)_(m)aryl or (C(R₁₀)₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; or

R_(4a) is absent and R₄ and R₅ taken together form an optionally substituted aryl or optionally substituted heteroaryl group;

each R₁₀ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, CN, halo and N(R₉)₂;

m is 0 or an integer of 1 to 6;

or a pharmaceutically acceptable salt thereof.

In a particular embodiment, there is provided a compound of formula (Ib):

wherein X is O;

R₁ is selected from:

R₆ and R₇ are independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, CN, CO₂R₉ and N(R₉)₂; or

R₆ and R₇ taken together with the atoms to which they are attached form an optionally substituted 6-membered aryl or heteroaryl ring;

each R₈ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, (C(R₁₀)₂)_(m)CO₂R₉ and (C(R₁₀)₂)_(m)N(R₉)₂;

each R₉ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl;

R₂ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, C₃₋₈ cycloalkyl and

R₁ and R₂ taken together form

wherein V is CH, O or S and R₁₁ and R₁₂ are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, halo, C₁₋₆haloalkyl, (CH₂)_(m)C₃₋₈cycloalkyl, (CH₂)_(m)aryl, (CH₂)_(m)heterocyclyl, (CH₂)_(m)heteroaryl and COR₁₃ where R₁₃ is selected from OH, OC₁₋₆alkyl, OC₂₋₆alkenyl, OC₂₋₆alkynyl and N(R₉)₂, wherein the cycloalkyl, heterocycloalkyl or heteroaryl ring of the bicyclic structure formed from R₁ and R₂ may be optionally substituted, or

R₁ and R₂ are both:

R₃ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and (C(R₁₀)₂)_(m)CO₂R₉;

R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl; and R₅ is hydrogen, (C(R₁₀)₂)_(m)aryl, (C(R₁₀)₂)_(m)heteroaryl, O(C(R₁₀)₂)_(m)aryl or O(C(R₁₀)₂)_(m)heteroaryl wherein the aryl and heteroaryl are optionally substituted; or

R_(4a) is CN and R₄ and R₅ are both hydrogen or taken together form:

where R₁₄ is hydrogen, (C(R₁₀)₂)_(m)aryl or (C(R₁₀)₂)_(m)heteroaryl where in the aryl and heteroaryl are optionally substituted; or

R_(4a) is absent and R₄ and R₅ taken together form an optionally substituted aryl or optionally substituted heteroaryl group;

each R₁₀ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, CN, halo and N(R₉)₂;

m is 0 or an integer of 1 to 6;

or a pharmaceutically acceptable salt thereof.

In particular embodiments of the compounds of formula (I), one or more of the following applies:

X is O;

R₁ is selected from:

especially

and more especially

R₂ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₃₋₈ cycloalkyl and

especially

C₁₋₄alkyl, C₂₋₄alkenyl, C₂₋₄alkynyl, C₃₋₆ cycloalkyl and

more especially

C₁₋₄alkyl, C₃₋₆ cycloalkyl and

wherein when R₁ is

especially where both R₁ and R₂ are

R₂ may be hydrogen when R₁ is

R₁ and R₂ together form a 5 or 6 membered cycloalkyl or heterocycloalkyl ring fused with a six-membered nitrogen-containing heteroaryl ring, wherein the cycloalkyl and heteroaryl ring may be optionally substituted; especially where R₁ and R₂ together are selected from:

wherein V is CH, O or S, especially CH or O; especially

wherein R₁₁ and R₁₂ are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, halo, C₁₋₆haloalkyl, (CH₂)_(m)C₃₋₈cycloalkyl, (CH₂)_(m)aryl, (CH₂)_(m)heterocyclyl, (CH₂)_(m)heteroaryl and COR₁₃ where R₁₃ is selected from OH, OC₁₋₆alkyl, OC₂₋₆alkenyl, OC₂₋₆alkynyl and N(R₉)₂, especially hydrogen, C₁₋₆alkyl and COR₁₃ where R₁₃ is selected from OC₁₋₆alkyl and N(R₉)₂, more especially hydrogen, C₁₋₃alkyl and COOC₁₋₃alkyl;

R₃ is selected from hydrogen, C₁₋₆alkyl, (CH₂)_(m)CO₂H and (CH₂)_(m)CO₂C₁₋₃alkyl, especially hydrogen, C₁₋₃alkyl, CH₂CO₂H and CH₂CO₂CH₃, more especially hydrogen; R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl; and R₅ is hydrogen, (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; especially where R₄ and R_(4a) are each independently hydrogen and R₅ is (CH₂)_(m)aryl, (CH₂)_(m)heteroaryl or Oaryl; where each aryl or heteroaryl ring are selected from phenyl, pyridinyl, indolyl, thiazolyl, oxazolyl, thiadiazolyl, benzothiophenyl and pyridizinyl, especially phenyl, indolyl and pyridinyl; and especially where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or

R_(4a) is CN and R₄ and R₅ are each hydrogen or taken together form:

where R₁₄ is hydrogen, (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl wherein the aryl and heteroaryl are optionally substituted; especially (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl; wherein each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or

R_(4a) is absent and R₄ and R₅ taken together form an optionally substituted aryl or optionally substituted heteroaryl group; especially where R₄ and R₅ taken together form a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 4-pyridazinyl ring, 2-furanyl, 3-furanyl, 2-thiophenyl ring, 3-thiophenyl ring, 2-thiazolyl ring, 3-thiazolyl ring, 4-thiazolyl ring, 3-isoxazolyl ring, 4-isoxazolyl ring, 5-isoxazolyl ring, 4-(1,2,3-thiadiazolyl) ring, 5-(1,2,3-thiadiazolyl) ring, 4-thiadiazolyl ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl, 3-benzothiophenyl ring, -3-(1H)-indolyl ring or a or a 4H-thieno[3,2-c]chromene ring, especially a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 2-furanyl, 2-thiophenyl ring, 3-thiazolyl ring, 3-isoxazolyl ring, 5-(1,2,3-thiadiazolyl) ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl ring, 3-(1H)-indolyl ring or a 4H-thieno[3,2-c]chromene ring, where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl;

R₆ and R₇ are independently selected from hydrogen, C₁₋₆alkyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, CN, CO₂H, CO₂C₁₋₃alkyl and N(R₉)₂, especially hydrogen, C₁₋₃alkyl, hydroxy, C₁₋₃alkoxy, C₁₋₃haloalkyl, C₁₋₃haloalkoxy, halo, CN, CO₂H, CO₂CH₃ and N(C₁₋₃alkyl)₂, more especially hydrogen, methyl, ethyl, or CF₃, most especially hydrogen or methyl; or

R₆ and R₇ taken together with the atoms to which they are attached form an optionally substituted phenyl, more especially an unsubstituted phenyl ring; each R₈ is independently selected from hydrogen, C₁₋₆alkyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, (CH₂)₁₋₃CO₂H and (CH₂)₁₋₃N(R₉)₂, especially hydrogen, C₁₋₃alkyl, hydroxy, C₁₋₃alkoxy, C₁₋₃haloalkyl, C₁₋₃haloalkoxy, halo, CH₂CO₂H, CH₂CH₂CO₂H and N(C₁₋₃alkyl)₂, more especially hydrogen, methyl, ethyl, or CF₃, most especially hydrogen or methyl;

each R₉ is independently selected from hydrogen, C₁₋₆alkyl and C₁₋₆haloalkyl, especially hydrogen, C₁₋₆alkyl, more especially hydrogen, C₁₋₃alkyl, most especially hydrogen and methyl;

each R₁₀ is independently selected from hydrogen, C₁₋₆alkyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, CN, halo and N(R₉)₂, especially, hydrogen, C₁₋₃alkyl, hydroxy, C₁₋₃alkoxy, C₁₋₃haloalkyl, C₁₋₃haloalkoxy, CN, halo and N(C₁₋₃alkyl)₂, more especially hydrogen, methyl, ethyl, hydroxy, methoxy, ethoxy, trifluoromethyl, trifluoromethyloxy, fluoro and chloro;

m is 0 or an integer 1 to 3, especially where m is 0 or an integer 1 or 2.

In some embodiments, the compound of formula (I) is a compound of formula (II):

wherein X, R₃, R₄, R_(4a) and R₅ are as defined for formula (I), R₁₁ and R₁₂ are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, halo, C₁₋₆haloalkyl, (CH₂)_(m)C₃₋₆ cycloalkyl, (CH₂)_(m)aryl, (CH₂)_(m)heterocyclyl, (CH₂)_(m)heteroaryl and COR₁₃ where R₁₃ is selected from OH, OC₁₋₆alkyl, OC₂₋₆alkenyl, OC₂₋₆alkynyl and N(R₉)₂ and r is 1, 2 or 3, or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (II) is a compound of formula (IIa):

wherein R₃, R₄, R_(4a), R₅, R₁₁ and R₁₂ are as defined for formula (II), or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (II) is a compound of formula (IIb):

wherein R₃, R₄, R_(4a), R₅, R₁₁ and R₁₂ are as defined for formula (II), or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (II) is a compound of formula (IIc):

wherein R₃, R₄, R_(4a), R₅, R₁₁ and R₁₂ are as defined for formula (II), or a pharmaceutically acceptable salt thereof.

In particular embodiments of the compounds of formula (II), one or more of the following applies:

X is O;

R₃ is selected from hydrogen, C₁₋₆alkyl, (CH₂)_(m)CO₂H and (CH₂)_(m)CO₂C₁₋₃alkyl, especially hydrogen, C₁₋₃alkyl, CH₂CO₂H and CH₂CO₂CH₃, more especially hydrogen; R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl; and R₅ is hydrogen, (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; especially where R₄ and R_(4a) are each independently hydrogen and R₅ is (CH₂)_(m)aryl, O(CH₂)_(m)aryl or (CH₂)_(m)heteroaryl; where each aryl or heteroaryl ring are selected from phenyl, pyridinyl, indolyl, thiazolyl, oxazolyl, thiadiazolyl, benzothiophenyl and pyridizinyl, especially phenyl, indolyl and pyridinyl; and especially where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or

R_(4a) is CN and R₄ and R₅ are each hydrogen or taken together form:

where R₁₄ is hydrogen, (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; especially (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl; wherein each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or

R_(4a) is absent and R₄ and R₅ taken together form an optionally substituted aryl or optionally substituted heteroaryl group; especially where R₄ and R₅ taken together form a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 4-pyridazinyl ring, 2-furanyl, 3-furanyl, 2-thiophenyl ring, 3-thiophenyl ring, 2-thiazolyl ring, 3-thiazolyl ring, 4-thiazolyl ring, 3-isoxazolyl ring, 4-isoxazolyl ring, 5-isoxazolyl ring, 4-(1,2,3-thiadiazolyl) ring, 5-(1,2,3-thiadiazolyl) ring, 4-thiadiazolyl ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl, 3-benzothiophenyl ring, -3-(1H)-indolyl ring or a 4H-thieno[3,2-c]chromene ring, especially a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 2-furanyl, 2-thiophenyl ring, 3-thiazolyl ring, 3-isoxazolyl ring, 5-(1,2,3-thiadiazolyl) ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl ring, 3-(1H)-indolyl ring or a 4H-thieno[3,2-c]chromene ring, where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; R₁₁ and R₁₂ are each independently selected from hydrogen, C₁₋₆alkyl, halo, C₁₋₆haloalkyl, (CH₂)_(m)C₃₋₈cycloalkyl, (CH₂)_(m)aryl, (CH₂)_(m)heterocyclyl, (CH₂)_(m)heteroaryl and COR₁₃ where R₁₃ is selected from OH, OC₁₋₆alkyl, and N(R₉)₂, especially where

R₁₁ and R₁₂ are independently selected from hydrogen, C₁₋₆alkyl, C₁₋₆haloalkyl, C₃-8cycloalkyl, CH₂phenyl, CH₂pyridyl, and CO C₁₋₆alkyl, more especially where Rn and R₁₂ are independently selected from hydrogen, C₁₋₃alkyl, C₁₋₃haloalkyl, fluoro, C₃₋₆cycloalkyl, CH₂phenyl, CH₂pyridyl and COC₁₋₃alkyl, most especially where Rn and R₁₂ are both hydrogen, both methyl, both ethyl or where one of R₁₁ and R₁₂ is hydrogen and the other is methyl, ethyl, fluoro, CH₂phenyl, CH₂pyridyl, CO₂methyl or CO₂ethyl.

Particular compounds of formula II include compounds 1 to 42, 156 to 159 as set out in Tables 1 to 3 and compounds 145, 170, 179 and 180.

In some embodiments, the compound of formula (I) is a compound of formula (III):

wherein X, Y₁, Y₂, R₂, R₃, R₄, R_(4a), R₅, R₆ and R₇ are as defined for formula (I), or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (III) is a compound of formula (IIIa):

wherein R₂, R₃, R₄, R_(4a), R₅, R₆, R₇ and R₈ are as defined for formula (III), or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (III) is a compound of formula (IIIb):

wherein R₂, R₃, R₄, R_(4a), R₅, R₆, R₇ and R₈ are as defined for formula (III), or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (III) is a compound of formula (IIIc):

wherein R₂, R₃, R₄, R_(4a), R₅, R₆, R₇ and each R₈ are as defined for formula (III), or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (III) is a compound of formula (IIId):

wherein R₃, R₄, R_(4a) and R₅ are as defined for formula (III), or a pharmaceutically acceptable salt thereof.

In particular embodiments of the compounds of formula (III), one or more of the following applies:

X is O;

R₁ is selected from:

especially

More especially

R₂ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₃₋₈ cycloalkyl and

especially

C₁₋₄alkyl, C₂₋₄alkenyl, C₂₋₄alkynyl, C₃₋₆ cycloalkyl and

more especially

C₁₋₄alkyl, C₃₋₆ cycloalkyl and

wherein when R₁ is

especially where both R₁ and R₂ are

R₃ is selected from hydrogen, C₁₋₆alkyl, (CH₂)_(m)CO₂H and (CH₂)_(m)CO₂C₁₋₃alkyl, especially hydrogen, C₁₋₃alkyl, CH₂CO₂H and CH₂CO₂CH₃, more especially hydrogen; R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl; and R₅ is hydrogen, (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; especially where R₄ and R_(4a) are each independently hydrogen and R₅ is (CH₂)_(m)aryl, O(CH₂)_(m)aryl or (CH₂)_(m)heteroaryl; wherein each aryl or heteroaryl ring are selected from phenyl, pyridinyl, indolyl, thiazolyl, oxazolyl, thiadiazolyl, benzothiophenyl and pyridizinyl, especially phenyl, indolyl and pyridinyl; and especially where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂-6alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂-3alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or R_(4a) is CN and R₄ and R₅ are each hydrogen or taken together form:

where R₁₄ is hydrogen, (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl wherein the aryl and heteroaryl are optionally substituted; especially (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl; wherein each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or

R_(4a) is absent and R₄ and R₅ taken together form an optionally substituted aryl or optionally substituted heteroaryl group; especially where R₄ and R₅ taken together form a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 4-pyridazinyl ring, 2-furanyl, 3-furanyl, 2-thiophenyl ring, 3-thiophenyl ring, 2-thiazolyl ring, 3-thiazolyl ring, 4-thiazolyl ring, 3-isoxazolyl ring, 4-isoxazolyl ring, 5-isoxazolyl ring, 4-(1,2,3-thiadiazolyl) ring, 5-(1,2,3-thiadiazolyl) ring, 4-thiadiazolyl ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl, 3-benzothiophenyl ring, -3-(1H)-indolyl ring or a 4H-thieno[3,2-c]chromene ring, especially a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 2-furanyl, 2-thiophenyl ring, 3-thiazolyl ring, 3-isoxazolyl ring, 5-(1,2,3-thiadiazolyl) ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl ring, 3-(1H)-indolyl ring or 4H-thieno[3,2-c]chromene ring, where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; R₆ and R₇ are independently selected from hydrogen, C₁₋₆alkyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, CN, CO₂H, CO₂C₁₋₃alkyl and N(R₉)₂, especially hydrogen, C₁₋₃alkyl, hydroxy, C₁₋₃alkoxy, C₁₋₃haloalkyl, C₁₋₃haloalkoxy, halo, CN, CO₂H, CO₂CH₃ and N(C₁₋₃alkyl)₂, more especially hydrogen, methyl, ethyl, or CF₃, most especially hydrogen or methyl; or

R₆ and R₇ taken together with the atoms to which they are attached form an optionally substituted phenyl, especially an unsubstituted or substituted phenyl ring, more especially an unsubstituted benzene ring;

each R₈ is independently selected from hydrogen, C₁₋₆alkyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, (CH₂)₁₋₃CO₂H and (CH₂)₁₋₃N(R₉)₂, especially hydrogen, C₁₋₃alkyl, hydroxy, C₁₋₃alkoxy, C₁₋₃haloalkyl, C₁₋₃haloalkoxy, halo, CH₂CO₂H, CH₂CH₂CO₂H and N(C₁₋₃alkyl)₂, more especially hydrogen, methyl, ethyl, or CF₃, most especially hydrogen or methyl;

each R₉ is independently selected from hydrogen, C₁₋₆alkyl and C₁₋₆haloalkyl, especially hydrogen, C₁₋₆alkyl, more especially hydrogen, C₁₋₃alkyl, most especially hydrogen and methyl.

Particular compounds of formula III include compounds 44 to 92 and 160 to 169 as set out in Tables 5 and 6, compounds 122 to 137, 140 to 144, 154, 155 and 181 to 191 as set out in Table 8, compounds 192 to 196 from Table 9 and compounds 146 to 153 as set out in Example 10 and Tables 10 and 11, especially compounds 44 to 54, 56 to 62, 76 to 92, 122 to 137, 140 to 144, 154, 155, 160 to 169, 181 to 183 and 192 to 194.

In some embodiments, the compound of formula (I) is a compound of formula (IV):

wherein X, Y₃, Y₄, R₂, R₃, R₄, R_(4a), R₅, R₆ and R₇ are as defined for formula (I), or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (IV) is a compound of formula (IVa):

wherein R₂, R₃, R₄, R_(4a), R₅, R₆, R₇ and R₈ are as defined for formula (IV) and Y₃ is S or NR₉, or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (IV) is a compound of formula (IVb):

wherein R₂, R₃, R₄, R_(4a), R₅, R₆ and R₇ are as defined for formula (IV), or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (IV) is a compound of formula (IVc):

wherein R₂, R₃, R₄, R_(4a), R₅, R₆, R₇ and R₈ are as defined for formula (IV), or a pharmaceutically acceptable salt thereof.

In particular embodiments of the compounds of formula (IV), one or more of the following applies:

X is O;

R₁ is selected from:

especially

More especially

R₂ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, and C₃₋₈ cycloalkyl, especially hydrogen, C₁₋₄alkyl, C₂₋₄alkenyl, C₂₋₄alkynyl and C₃₋₆ cycloalkyl, more especially hydrogen, C₁₋₄alkyl and C₃₋₆ cycloalkyl,

R₃ is selected from hydrogen, C₁₋₆alkyl, (CH₂)_(m)CO₂H and (CH₂)_(m)CO₂C₁₋₃alkyl, especially hydrogen, C₁₋₃alkyl, CH₂CO₂H and CH₂CO₂CH₃, more especially hydrogen; R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl; and R₅ is hydrogen, (CH₂)_(m)aryl, O(CH₂)_(m)aryl or (CH₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; especially where R₄ and R_(4a) are each independently hydrogen and R₅ is (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl; where each aryl or heteroaryl ring are selected from phenyl, pyridinyl, indolyl, thiazolyl, oxazolyl, thiadiazolyl, benzothiophenyl and pyridizinyl, especially phenyl, indolyl and pyridinyl; and especially where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or

R_(4a) is CN and R₄ and R₅ are each hydrogen or taken together form:

where R₁₄ is hydrogen, (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl wherein the aryl and heteroaryl are optionally substituted; especially (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl; wherein each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or

R_(4a) is absent and R₄ and R₅ taken together form an optionally substituted aryl or optionally substituted heteroaryl group; especially where R₄ and R₅ taken together form a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 4-pyridazinyl ring, 2-furanyl, 3-furanyl, 2-thiophenyl ring, 3-thiophenyl ring, 2-thiazolyl ring, 3-thiazolyl ring, 4-thiazolyl ring, 3-isoxazolyl ring, 4-isoxazolyl ring, 5-isoxazolyl ring, 4-(1,2,3-thiadiazolyl) ring, 5-(1,2,3-thiadiazolyl) ring, 4-thiadiazolyl ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl, 3-benzothiophenyl ring, -3-(1H)-indolyl ring or 4H-thieno[3,2-c]chromene ring, especially a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 2-furanyl, 2-thiophenyl ring, 3-thiazolyl ring, 3-isoxazolyl ring, 5-(1,2,3-thiadiazolyl) ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl ring, 3-(1H)-indolyl ring or a 4H-thieno[3,2-c]chromene ring, where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl;

R₆ and R₇ are independently selected from hydrogen, C₁₋₆alkyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, CN, CO₂H, CO₂C₁₋₃alkyl and N(R₉)₂, especially hydrogen, C₁₋₃alkyl, hydroxy, C₁₋₃alkoxy, C₁₋₃haloalkyl, C₁₋₃haloalkoxy, halo, CN, CO₂H, CO₂CH₃ and N(C₁₋₃alkyl)₂, more especially hydrogen, methyl, ethyl, or CF₃, most especially hydrogen or methyl; or

R₆ and R₇ taken together with the atoms to which they are attached form an optionally substituted phenyl, especially an unsubstituted or substituted phenyl ring, more especially an unsubstituted benzene ring;

Each R₈ is independently selected from hydrogen, C₁₋₆alkyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, (CH₂)₁₋₃CO₂H and (CH₂)₁₋₃N(R₉)₂, especially hydrogen, C₁₋₃alkyl, hydroxy, C₁₋₃alkoxy, C₁₋₃haloalkyl, C₁₋₃haloalkoxy, halo, CH₂CO₂H, CH₂CH₂CO₂H and N(C₁₋₃alkyl)₂, more especially hydrogen, methyl, ethyl, or CF₃, most especially hydrogen or methyl;

Each R₉ is independently selected from hydrogen, C₁₋₆alkyl and C₁₋₆haloalkyl, especially hydrogen, C₁₋₆alkyl, more especially hydrogen, C₁₋₃alkyl, most especially hydrogen and methyl.

Particular compounds of formula (IV) include compounds 93 to 119 and 163 to 169 as set out in Table 6 especially compounds 110 to 113, 116, 117 and 163 to 169.

In some embodiments, the compound of formula (I) is a compound of formula (V):

wherein R₂, R₃, R₄, R_(4a) and R₅, are as defined for formula (I).

In particular embodiments of the compounds of formula (V), one or more of the following applies:

R₂ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, and C₃₋₈ cycloalkyl, especially hydrogen, C₁₋₄alkyl, C₂₋₄alkenyl, C₂₋₄alkynyl and C₃₋₆ cycloalkyl, more especially hydrogen, C₁₋₄alkyl and C₃₋₆ cycloalkyl,

R₃ is selected from hydrogen, C₁₋₆alkyl, (CH₂)_(m)CO₂H and (CH₂)_(m)CO₂C₁₋₃alkyl, especially hydrogen, C₁₋₃alkyl, CH₂CO₂H and CH₂CO₂CH₃, more especially hydrogen;

R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl; and R₅ is hydrogen, (CH₂)_(m)aryl, O(CH₂)_(m)aryl or (CH₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; especially where

R₄ and R_(4a) are each independently hydrogen and R₅ is (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl; where each aryl or heteroaryl ring are selected from phenyl, pyridinyl, indolyl, thiazolyl, oxazolyl, thiadiazolyl, benzothiophenyl and pyridazinyl, especially phenyl, indolyl and pyridinyl; and especially where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂-3alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or R_(4a) is CN and R₄ and R₈ are each hydrogen or taken together form:

where R₁₄ is hydrogen, (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl wherein the aryl and heteroaryl are optionally substituted; especially (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl; where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or

R_(4a) is absent and R₄ and R₅ taken together form an optionally substituted aryl or optionally substituted heteroaryl group; especially where R₄ and R₅ taken together form a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 4-pyridazinyl ring, 2-furanyl, 3-furanyl, 2-thiophenyl ring, 3-thiophenyl ring, 2-thiazolyl ring, 3-thiazolyl ring, 4-thiazolyl ring, 3-isoxazolyl ring, 4-isoxazolyl ring, 5-isoxazolyl ring, 4-(1,2,3-thiadiazolyl) ring, 5-(1,2,3-thiadiazolyl) ring, 4-thiadiazolyl ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl, 3-benzothiophenyl ring, -3-(1H)-indolyl ring or a 4H-thieno[3,2-c]chromene ring, especially a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 2-furanyl, 2-thiophenyl ring, 3-thiazolyl ring, 3-isoxazolyl ring, 5-(1,2,3-thiadiazolyl) ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl ring, 3-(1H)-indolyl ring or a 4H-thieno[3,2-c]chromene ring, where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl;

Each R₈ is independently selected from hydrogen, C₁₋₆alkyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, (CH₂)₁₋₃CO₂H and (CH₂)₁₋₃N(R₉)₂, especially hydrogen, C₁₋₃alkyl, hydroxy, C₁₋₃alkoxy, C₁₋₃haloalkyl, C₁₋₃haloalkoxy, halo, CH₂CO₂H, CH₂CH₂CO₂H and N(C₁₋₃alkyl)₂, more especially hydrogen, methyl, ethyl, or CF₃, most especially hydrogen or methyl;

Each R₉ is independently selected from hydrogen, C₁₋₆alkyl and C₁₋₆haloalkyl, especially hydrogen, C₁₋₆alkyl, more especially hydrogen, C₁₋₃alkyl, most especially hydrogen and methyl.

Particular compounds of formula V include compounds 120, 121, 138 and 139 as set out in Table 7.

In some embodiments, the compound of formula (I) is a compound of formula (VI):

wherein X, V, R₃, R₄, R_(4a) and R₅ are as defined for formula (I), R₁₁ and R₁₂ are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, halo, C₁₋₆haloalkyl, (CH₂)_(m)C₃₋₆ cycloalkyl, (CH₂)_(m)aryl, (CH₂)_(m)heterocyclyl, (CH₂)_(m)heteroaryl and COR₁₃ where R₁₃ is selected from OH, OC₁₋₆alkyl, OC₂₋₆alkenyl, OC₂₋₆alkynyl and N(R₉)₂ and s is 0, 1 or 2, or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (VI) is a compound of formula (VIa):

wherein R₃, R₄, R_(4a), R₅, R₁₁ and R₁₂ are as defined for formula (VI), or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (VI) is a compound of formula (VIb):

wherein R₃, R₄, R_(4a), R₅, R₁₁ and R₁₂ are as defined for formula (VI), or a pharmaceutically acceptable salt thereof.

In some embodiments, the compound of formula (VI) is a compound of formula (VIc):

wherein R₃, R₄, R_(4a), R₅, R₁₁ and R₁₂ are as defined for formula (VI) or a pharmaceutically acceptable salt thereof.

In particular embodiments of the compounds of formula (VI), one or more of the following applies:

X is O;

V is O;

R₃ is selected from hydrogen, C₁₋₆alkyl, (CH₂)_(m)CO₂H and (CH₂)_(m)CO₂C₁₋₃alkyl, especially hydrogen, C₁₋₃alkyl, CH₂CO₂H and CH₂CO₂CH₃, more especially hydrogen; R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl; and R₅ is hydrogen, (CH₂)_(m)aryl, O(CH₂)_(m)aryl or (CH₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; especially where R₄ and R_(4a) are each independently hydrogen and R₅ is (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl; where each aryl or heteroaryl ring are selected from phenyl, pyridinyl, indolyl, thiazolyl, oxazolyl, thiadiazolyl, benzothiophenyl and pyridizinyl, especially phenyl, indolyl and pyridinyl; and especially where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or

R_(4a) is CN and R₄ and R₅ are each hydrogen or taken together form:

where R₁₄ is hydrogen, (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl where aryl and heteroaryl are optionally substituted; especially (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl; where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl; or

R_(4a) is absent and R₄ and R₅ taken together form an optionally substituted aryl or optionally substituted heteroaryl group; especially where R₄ and R₅ taken together form a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 4-pyridazinyl ring, 2-furanyl, 3-furanyl, 2-thiophenyl ring, 3-thiophenyl ring, 2-thiazolyl ring, 3-thiazolyl ring, 4-thiazolyl ring, 3-isoxazolyl ring, 4-isoxazolyl ring, 5-isoxazolyl ring, 4-(1,2,3-thiadiazolyl) ring, 5-(1,2,3-thiadiazolyl) ring, 4-thiadiazolyl ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl, 3-benzothiophenyl ring, -3-(1H)-indolyl ring or a 4H-thieno[3,2-c]chromene ring, especially a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 2-furanyl, 2-thiophenyl ring, 3-thiazolyl ring, 3-isoxazolyl ring, 5-(1,2,3-thiadiazolyl) ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl ring, 3-(1H)-indolyl ring or a 4H-thieno[3,2-c]chromene ring, where each aryl or heteroaryl ring may be unsubstituted or substituted by one or more substituents selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, hydroxy, —OC₁₋₆alkyl, —OC₂₋₆alkenyl, —OC₂₋₆alkynyl, —OC₁₋₆haloalkyl, N(R₉)₂, (CH₂)_(q)N(R₁₅)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer of 1 to 6 and each R₁₅ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, especially C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl, C₁₋₃haloalkyl, halo, hydroxy, —OC₁₋₃alkyl, —OC₂₋₃alkenyl, —OC₂₋₃alkynyl, —OC₁₋₃haloalkyl, N(C₁₋₃alkyl)₂ and O(CH₂)_(q)N(R₁₅)₂, wherein q is an integer from 1 to 3 and each R₁₅ is independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl or two R₁₅ taken together with the nitrogen atom to which they are attached form a 5 or 6 membered heterocyclic ring, more especially methyl, ethyl, propyl, isopropyl, chloro, fluoro, trifluoromethyl, methoxy, ethoxy, dimethyl amino, diethyl amino, —OCH₂CH₂N(CH₃)₂, —OCH₂CH₂piperidinyl, OCH₂CH₂pyrrolyl and —OCH₂CH₂CH₂piperidinyl;

R₁₁ and R₁₂ are each independently selected from hydrogen, C₁₋₆alkyl, halo, C₁₋₆haloalkyl, (CH₂)_(m)C₃₋₈cycloalkyl, (CH₂)_(m)aryl, (CH₂)_(m)heterocyclyl, (CH₂)_(m)heteroaryl and COR₁₃ where R₁₃ is selected from OH, OC₁₋₆alkyl, and N(R₉)₂, especially where R₁₁ and R₁₂ are independently selected from hydrogen, C₁₋₆alkyl, C₁₋₆haloalkyl, C₃-8cycloalkyl, CH₂phenyl, CH₂pyridyl, and CO C₁₋₆alkyl, more especially where Rn and R₁₂ are independently selected from hydrogen, C₁₋₃alkyl, C₁₋₃haloalkyl, fluoro, C₃-6cycloalkyl, CH₂phenyl, CH₂pyridyl and COC₁₋₃alkyl, most especially where Rn and R₁₂ are both hydrogen, both methyl, both ethyl or where one of R₁₁ and R₁₂ is hydrogen and the other is methyl, ethyl, fluoro, CH₂phenyl, CH₂pyridyl, CO₂methyl or CO₂ethyl.

Particular compounds of formula VI include compounds 171 to 178 in Table 12.

The compounds of the invention may be synthesised from commercially available starting materials using known methods. For example, the hydrazides may be prepared by reacting an appropriate ketone with a carboxylic acid hydrazine in the presence of a catalytic amount of acid.

Suitable catalytic acids include concentrated hydrochloric acid or toluene sulphonic acid.

The resulting hydrazides may be further derivatised, for example by alkylation of hydroxy groups or formation of double bonds from ketones and aldehydes. Suitable reactions are provided in the Examples below.

EXAMPLES

Abbreviations ACN acetonitrile h Hour(s) cone. concentrated K₂CO₃ Potassium carbonate DMF N,N-Dimethyl formamide MeOH methanol EtOH Ethanol min minute EtOAc Ethyl Acetate MS Mass Spectrometry THF Tetrahydrofuran LiOH Lithium hydroxide rt Room temperature o/n Over night

A range of acyl hydrazones can be prepared by the synthetic route depicted in Scheme 1. Heating an equimolar mixture of a dihydroquinolone ketone derivative A and substituted acyl hydrazides in ethanol or other suitable solvent, with a catalytic amount of acid, furnished target acyl hydrazone products B. Ketone starting materials were available from commercial suppliers or known literature methods. For example, 5,6-dihydro-7,7-dimethylquinolin-8-one could be prepared, as described by Chuang Bing et al, New Journal of Chemistry 2016, 40, 9329-9346. Ethyl 8-oxo-5,6,7,8-tetrahydroquinoline-7-carboxylate starting material is known in the literature (Takashi et al, Synthesis 2005, 10, 1593-1600). The compound could be synthesised by heating 6,7-dihydroquinolin-8(5H)-one, sodium hydride and diethyl carbonate at 130° C.

Example: (Table 1) (E)-N′-(6,7-Dihydroquinolin-8(5H)-ylidene)nicotinohydrazide (1)

To a solution of 6,7-Dihydroquinolin 8(5H)-one (622 mg, 4.22 mmol) in EtOH was added nicotinic acid hydrazide (575 mg, 4.22 mmol) followed by the addition of catalytic para-toluene sulphonic acid (7 mg). The reaction was heated to 45° C. for 1 h, then left to cool overnight. A cream coloured solid was collected by filtration which was suspended in MeOH. The filtrate was cooled to 4° C. overnight. Off-white needles were collected by filtration to afford target compound (E)-N′-(6,7-dihydroquinolin-8(5H-)-ylidene)nicotinohydrazide 1 (112 mg). ¹H NMR (600 MHz, d6-DMSO) δ 1.96 (t, J=6.0 Hz, 2H), 2.99 (t, J=6.0 Hz, 4H), 7.64 (dd, J=7.8, 4.8 Hz, 1H), 7.85 (br s, 1H), 8.38 (d, J=6.6 Hz, 2H), 8.68 (d, J74.8 Hz, 1H), 8.81 (d, J=4.8 Hz, 1H), 9.13 (s, 1H), 11.64 (s, 1H). MS m/z 267.12 [M+H]⁺.

TABLE 1 Selected Data for Compounds prepared via Scheme 1 Mass Spec Compound Structure NMR [M + H]⁺ 2

¹H NMR (600 MHz, d6-DMSO) δ 1.97 (t, J = 6.0 Hz, 2H), 2.77 (t, J = 6.0 Hz, 2H), 2.90-2.94 (m, 2H), 7.50 (dd, J = 14.0, 6.6 Hz, 1H), 7.63-7.66 (m, 1H), 7.86-7.89 (m, 1H), 8.01-8.05 (m, 1H), 8.11-8.14 (m, 1H), 8.71-8.74 (m, 1H), 8.75- 8.78 (m, 1H), 16.23 (s, 1H), m/z 267.12  3

¹H NMR (600 MHz, d6-DMSO) δ 1.96 (t, J = 6.0 Hz, 2H), 2.77 (t, J = 6.0 Hz, 2H), 2.93 (t, J = 6.0 Hz, 2H), 7.55 (dd, J = 7.8, 4.8 Hz, 1H), 7.80 (dd, J = 4.2, 1.2 Hz, 2H), 7.92 (d, J = 7.8 Hz, 1H), 8.77 (d, J = 4.2 Hz, 1H), 8.82 (dd, J = 4.8, 1.2 Hz, 2H). m/z 267.12  4

¹H NMR (600 MHz, d6-DMSO) δ 1.43-1.48 (m, 3H), 1.98 (t, J = 6.0 Hz, 2H), 2.86 (t, J = 6.0 Hz, 2H), 2.99 (t, J = 6.0 Hz, 2H), 4.22- 4.27 (m, 2H), 7.13 (t, J = 7.8 Hz, 1H), 7.25 (d, J = 7.8 Hz, 1H), 7.56- 8.00 (m, 1H), 7.90 (d, J = 4.8 Hz, 2H), 8.41 (d, J = 7.8 Hz, 1H), 8.68 (d, J = 4.8 Hz, 1H). m/z 310.16  5

¹H NMR (600 MHz, d6-DMSO) δ 1.35 (t, J = 6.6 Hz, 3H), 1.96 (t, J = 6.0 Hz, 2H), 2.94-3.02 (m, 4H), 4.10 (q, J = 14.4, 6.6 Hz, 2H), 7.18 (dd, J = 8.4, 2.4 Hz, 1H), 7.43-7.46 (m, 2H), 7.51 (d, J = 8.4 Hz, 1H), 7.26 (dd, J = 6.6, 1.2 Hz, 1H), 8.44 (d, J = 8.4 Hz, 1H), 8.69 (d, J = 4.8 Hz, 1H), 11.37 (s, 1H). m/z 310.16  6

¹H NMR (600 MHz, d6-DMSO) δ 1.91-1.95 (m, 2H), 2.76 (t, J = 6.0 Hz, 2H), 2.92 (t, J = 6.0 Hz, 2H), 3.84 (s, 3H), 7.19 (dd, J = 7.8, 1.8 Hz, 1H), 7.40 (s, 1H), 7.46 (d, J = 7.2 Hz, 1H), 7.48-7.54 (m, 2H), 7.91 (d, J = 6.0 Hz, 1H), 8.68 (s, 1H). m/z 296.14  7

¹H NMR (600 MHz, d6-DMSO) δ 1.95 (t, J = 6.0 Hz, 2H), 2.93-3.01 (m, 4H), 3.84 (s, 3H), 3.86 (s, 3H), 7.09 (d, J = 8.4 Hz, 1H), 7.51 (s, 1H), 7.61 (dd, J = 8.4, 1.8 Hz, 1H), 7.91 (d, J = 6.6 Hz, 1H), 8.42 (d, J = 6.6 Hz, 1H), 8.60 (s, 1H), 11.20 (br s, 1H). m/z 326.1498 8

¹H NMR (600 MHz, d6-DMSO) δ 1.98 (t, J = 6.0 Hz, 2H), 2.85 (t, J = 6.0 Hz, 2H), 2.99 (t, J = 6.0 Hz, 2H), 3.91 (s, 3H), 7.13 (t, J = 7.8 Hz, 1H), 7.26 (d, J = 7.8 Hz, 1H), 7.60 (t, J = 7.8 Hz, 1H), 7.85 (s, 1H), 7.91-7.94 (m, 1H), 8.15 (d, J = 7.8 Hz, 1H), 8.65 (s, 1H), 11.36 (s, 1H). m/z 296.14  9

¹H NMR (600 MHz, d6-DMSO) δ 1.95 (t, J = 6.6 Hz, 2H), 2.75 (s, 2H), 2.92 (t, J = 6.6 Hz, 1H), 3.84 (s, 3H), 7.12 (t, J = 7.8 Hz, 2H), 7.52 (dd, J = 7.8, 3.6 Hz, 1H), 7.85- 7.91 (m, 3H), 8.74 (d, J = 3.6 Hz, 1H) m/z 296.14  10

¹H NMR (600 MHz, d6-DMSO) δ 1.95 (t, J = 5.4 Hz, 2H), 2.75-2.80 (m, 2H), 2.92 (t, J = 5.4 Hz, 2H), 7.48-7.52 (m, 1H), 7.57-7.62 (m, 3H), 7.82-7.88 (m, 3H), 8.72 (d, J = 3.0 Hz, 1H). m/z 266.13  11

¹H NMR (600 MHz, d6-DMSO) δ 1.99 (t, J = 6.0 Hz, 2H), 2.79-2.84 (m, 2H), 2.98 (t, J = 6.0 Hz, 2H), 7.13 (d, J = 7.2 Hz, 1H), 7.51 (dd, J = 8.4, 2.4 Hz, 1H), 7.87-7.92 (m, 2H), 8.37 (br s, 1H) 8.68 (s, 1H), 11.65 (br s, 1H), 12.28 (br s, 1H). m/z 316.08  12

¹H NMR (600 MHz, d6-DMSO) δ 1.95 (m, 2H), 2.82 (br s, 2H), 2.89 (s, 2H), 6.98 (s, 1H), 7.05 (s, 1H), 7.42 (d, J = 7.2 Hz, 1H), 7.54 (dd, J = 7.8, 4.8 Hz, 1H), 7.93 (d, J = 7.2 Hz, 1H), 7.99 (dd, J = 7.8 Hz, 1.8 Hz, 1H), 8.59 (d, J = 3.6 Hz, 1H), 11.56 (br s, 1H), 11.85 (br s, 1H). m/z 282.12  13

¹H NMR (600 MHz, d6-DMSO) δ 1.96 (t, J = 6.0 Hz, 2H), 2.40 (s, 3H), 2.96-3.02 (m, 4H), 7.41-7.46 (m 2H), 7.72-7.77 (m, 2H), 7.94 (dd, J = 7.8, 5.4 Hz, 1H), 8.46 (d, J = 7.8 Hz, 1H), 8.69 (d, J = 5.4 Hz, 1H), 11.40 (s, 1H). m/z 280.14  14

¹H NMR (600 MHz, d6-DMSO) δ 1.96 (t, J = 6.0 Hz, 2H), 2.30 (s, 3H), 2.32 (s, 3H), 2.94-3.01 (m, 4H), 7.30 (d, J = 7.8 Hz, 1H), 7.68 (d, J = 7.8 Hz, 1H), 7.74 (s, 1H), 7.92 (t, J = 6.6 Hz, 1H), 8.44 (d, J = 6.6 Hz, 1H), 8.68 (d, J = 4.8 Hz, 1H). m/z 294.1600 15

¹H NMR (600 MHz, d6-DMSO) some peaks not well resolved δ 1.93 (t, J = 6.0 Hz, 2H), 2.82 (t, J = 6.0 Hz, 2H), 2.97 (t, J = 6.0 Hz, 2H), 7.45 (t, J = 7.8 Hz, 1H), 7.58 (t, J = 7.8 Hz, 1H), 7.87-7.93 (m, 1H), 7.97-8.02 (m, 2H), 8.39-8.44 (m, 1H), 8.66 (s, 1H), 11.61 (s, 1H) m/z 300.09  16

¹H NMR (600 MHz, d6-DMSO) δ 1.96 (t, J = 6.0 Hz, 2H), 2.77 (t, J = 6.0 Hz, 2H), 2.95 (t, J = 6.0 Hz, 2H), 7.54 (dd, J = 7.8 Hz, 4.8 Hz, 1H), 7.64 (t, J = 7.8 Hz, 1H), 7.71 (d, J = 7.8 Hz, 1H), 7.84 (d, J = 7.8 Hz, 1H), 7.88 (s, 1H), 7.93 (d, J = 7.8 Hz, 1H), 8.70 (d, J = 4.8 Hz, 1H). m/z 300.09  17

¹H NMR (600 MHz, d6-DMSO) δ 1.90 (t, J = 6.0 Hz. 2H), 2.76-3.01 (m, 4H), 4.00 (s, 3H), 7.28 (d, J = 7.8 Hz, 1H), 7.30-7.35 (m, 1H), 7.60-7.66 (m, 2H), 7.85 (d, J = 7.8 Hz, 1H), 8.53 (t, J = 4.2 Hz, 1H), 10.92 (s, 1H) m/z 330.10  18

¹H NMR (600 MHz, d6-DMSO) δ 1.91 (t, J = 6.0 Hz. 2H), 2.34 (s, 3H), 2.94 (t, J = 6.0 Hz, 2H), 2.95 (s, 2H), 7.27-7.32 (m, 2H), 7.39- 7.46 (m, 2H), 7.87 (br s, 1H), 8.34 (s, 1H), 8.63 (s, 1H), 11.41 (s, 1H). m/z 280.15  19

¹H NMR (600 MHz, d6-DMSO) δ 2.03 (t, J = 6.0 Hz, 2H), 2.50 (s, 3H), 3.05-3.11 (m, 4H), 7.45 (d, J = 7.8 Hz, 2H), 7.96 (d, J = 7.8 Hz, 2H), 8.54 (d, J = 7.8 Hz, 1H), 8.03 (d, J = 6.0 Hz, 1H), 8.79 (s, 1H), 11.4 (s, 1H). m/z 280.15  20

¹H NMR (600 MHz, d6-DMSO) δ 1.95-1.98 (m, 2H), 2.96-3.01 (m, 4H), 7.88-7.93 (m, 3H), 8.10-8.14 (m, 2H), 8.40-8.43 (m, 1H), 8.69 (d, J = 4.8 Hz, 1H), 11.61 (s, 1H). m/z 334.12  21

¹H NMR (600 MHz, d6-DMSO) δ 1.96 (t, J = 6.0 Hz, 2H), 2.76 (t, J = 6.0 Hz, 2H), 2.93 (t, J = 6.0 Hz, 2H), 3.86 (s, 3H), 6.94 (d, J = 7.8 Hz, 1H), 7.37-7.43 (m, 2H), 7.51 (dd, J = 7.8, 4.8 Hz, 1H), (d, J = 7.8 Hz, 1H), 8.71 (d, J = 4.8 Hz, 1H), 9.89 (br s, 1H). m/z 312.13  22

¹H NMR (600 MHz, d6-DMSO) δ 1.92-1.99 (m, 2H), 2.56 (s, 3H), 2.74-2.79 (m, 2H), 2.88-2.94 (m, 2H), 7.46 (d, J = 7.8 Hz, 1H), 7.52 (dd, J = 6.6, 4.2 Hz, 1H), 7.91 (d, J = 7.2 Hz, 1H), 8.12 (d, J = 7.2 Hz, 1H), 8.72 (s, 1H), 8.93 (s, 1H) m/z 281.1392 23

¹H NMR (600 MHz, d6-DMSO) δ 1.87 (t, J = 6.0 Hz, 2H), 2.80-2.84 (m, 4H), 2.97 (s, 3H), 7.36 (dd, J = 7.2, 4.8 Hz, 1H), 7.66 (d, J = 7.2 Hz, 1H), 8.68 (d, J = 4.8 Hz, 1H), 11.62 (s, 1H). m/z 288.0913 24

¹H NMR (600 MHz, d6-DMSO) δ 1.96 (t, J = 6.0 Hz, 2H), 2.92-2.99 (m, 4H), 7.42-7.58 (m, 2H), 7.72- 7.80 (m, 1H), 8.00-8.06 (m, 2H), 8.15-8.26 (m, 1H), 8.51-8.62 (m, 1H), 8.69 (s, 1H), 11.48 (br s, 1H). m/z 322.1009 25

¹H NMR (600 MHz, d6-DMSO) δ 1.97 (quintet, J = 6.0 Hz, 2H), 2.94-2.99 (m, 4H), 5.32 (s, 2H), 6.97-7.02 (m, 2H), 8.07 (s, 1H), 7.84-7.88 (m, 1H), 7.25 (d, J = 7.2 Hz, 1H), 7.45 (d, J = 7.2 Hz, 1H), 8.36 (s, 1H), 8.73 (d, J = 4.8 Hz, 1H), 11.43 (s, 1H). m/z 376.11  26

¹H NMR (500 MHz, d6-DMSO) δ 1.24 (s, 6H), 1.93 (t, J = 6.5 Hz, 2H), 2.95 (t, J = 6.5 Hz, 2H), 3.84 (s, 3H), 3.86 (s, 3H), 7.14 (d, J = 8.5 Hz, 1H), 7.42 (s, 1H), 7.48- 7.52 (m, 2H), 7.90 (d, J = 7.5 Hz, 1H), 8.71 (d, J = 3.5 Hz, 1H), 15.98 (s, 1H). m/z 354.18  27

¹H NMR (600 MHz, d6-DMSO) 3:1 geometric isomers-major isomer δ 1.25 (s, 6H), 1.84 (t, J = 6.6 Hz, 2H), 2.96 (t, J = 6.6 Hz, 2H), 7.52-7.57 (m, 2H), 7.63 (dd, J = 7.8, 4.8 Hz, 1H), 7.92 (d, J = 7.8 Hz, 1H), 8.25 (d, J = 7. Hz, 1H), 8.73 (d, J = 3.6 Hz, 1H), 8.80 (d, J = 4.8 Hz, 1H), 9.06 (s, 1H), 11.98 (br s, 1H). m/z 295.1554 28

¹H NMR (600 MHz, d6-DMSO) 1:1 geometric isomers δ 1.96- 2.02 (m, 4H), 2.80 (t, J = 6.0 Hz, 2H), 2.95 (t, J = 6.0 Hz, 2H), 2.99- 3.05 (m, 4H), 7.52 (dd, J = 7.8, 4.8 Hz, 1H), 7.90-8.03 (m, 4H), 8.30- 8.35 (m, 2H), 8.52 (d, J = 13.8 Hz, 1H), 8.66 (d, J = 3.0 Hz, 1H), 8.73 (d, J = 4.8 Hz, 1H), 9.43-9.46 (m, 1H), 9.51 (d, J = 4.2 Hz, 1H), 11.32 (br s, 1H). m/z 268.1196 29

¹H NMR (600 MHz, d6-DMSO) δ 1.93 (t, J = 6.0 Hz, 2H), 7.72 (t, J = 6.0 Hz, 2H), 2.89 (t, J = 6.0 Hz, 2H), 2.91 (s, 3H), 2.93 (s, 3H), 6.79 (d, J = 9.0 Hz, 1H), 7.48 (d, J = 7.8 Hz, 1H), 7.74 (d, J = 7.2 Hz, 2H), 7.86 (d, J = 7.2 Hz. 1H), 8.72 (d, 3.6 Hz, 1H), m/z 309.17  30

¹H NMR (500 MHz, d6-DMSO) δ 1.35 (s, 6H), 1.85 (t, J = 6.0 Hz, 2H), 2.96 (t, J = 6.0 Hz, 2H), 3.31 (s, 3H), 7.57 (dd, J = 8.0, 4.5 Hz, 1H), 7.93 (d, J = 6.5 Hz, 1H), 8.50 (d, J = 4.5 Hz, 1H), 15.62 (s, 1H) m/z 316.12  31

¹H NMR (600 MHz, d6-DMSO) δ 1.12 (t, J = 7.2 Hz, 3H), 2.22-2.26 (m, 1H), 2.34-2.38 (m, 2H), 2.84- 2.97 (m, 2H), 2.96 (s, 3H), 4.04 (t, J = 6.0 Hz, 1H), 4.15 (q, J = 7.2, 1.8 Hz, 2H), 7.56 (dd, J = 7.2, 4.2 Hz, 1H), 7.93 (d, J = 7.2 Hz, 1H), 8.73 (d, J = 4.2 Hz, 1H). m/z 360.1123 32

¹H NMR (600 MHz, d6-DMSO) δ 1.91-1.97 (m, 2H), 2.61 (s, 3H), 2.66 (s, 3H), 2.88 (t, J = 7.8 Hz, 2H), 2.98 (t, J = 7.8 Hz, 2H) 7.95 (app t, J = 7.2 Hz, 1H), 8.47 (d, J = 9.6 Hz, 1H), 8.73 (d, J = 7.2 Hz, 1H), 11.54 (br s, 1H). m/z 301.1119 33

¹H NMR (600 MHz, d6-DMSO) δ 1.94 (t, J = 6.0 Hz, 2H), 2.51 (s, 3H), 2.92 (t, J = 6.0 Hz, 2H), 2.99 (t, J = 6.0 Hz, 2H), 6.75 (s, 1H), 7.92 (s, 1H), 8.41 (s, 1H), 8.69 (d, J = 4.8 Hz, 1H), 11.58 (br s, 1H). m/z 271.1186 156

¹H NMR (500 MHz, d6-DMSO) δ 1.93 (t, J = 5.5 Hz, 2H), 2.84 (t, J = 5.5 Hz, 2H), 2.95-2.99 (m, 2H), 7.52-7.56 (m, 2H), 7.67-7.74 (m, 2H), 7.92 (s, 1H), 8.42 (d, J = 6.0 Hz, 1H), 8.68 (s, 1H), 11.63 (s, 1H) m/z 350.1113 157

m/z 310.1187 158

m/z 284.1193 159

m/z 314.1301 180

¹H NMR (400 MHz, d6-DMSO) δ 1.98 (t, J = 6.0 Hz, 2H), 2.48 (s, 3H), 2.78 (t, J = 6.0 Hz, 2H), 2.94 (t, J = 6.0 Hz, 2H), 6.95 (t, J = 7.2 Hz, 1H), 7.39 (d, J = 7.2 Hz, 1H), 7.54- 7.58 (m, 2H), 7.94 (d, J = 7.2 Hz, 1H), 8.80 (d, J = 4.4 Hz, 1H). m/z 296.1392

Similarly, fused cyclopentane derivatives D could be synthesised according to Scheme 2.

Example 2 (Table 2) (E)-N′-(5H-Cyclopenta[b]pyridin-7(6H)-ylidene)-3,4-dimethoxybenzohydrazide (38)

To a solution of 5H-cyclopenta[b]pyridin-7(6H)-one (40 mg, 0.30 mmol) in MeOH (8 mL) was added 3,4-dimethoxybenzhydrazide (59 mg, 1 mol eq), followed by one drop of concentrated hydrochloric acid. The reaction was stirred overnight. An off-white solid was collected by filtration to afford the desired (E)-N′-(5H-cyclopenta[b]pyridin-7(6H)-ylidene)-3,4-dimethoxybenzohydrazide 38 (30 mg). ¹H NMR (600 MHz, d6-DMSO) δ 2.95 (t, J=6.0 Hz, 2H), 3.11-3.16 (m, 2H), 3.84 (s, 3H), 3.87 (s, 3H), 7.14 (d, J=8.4 Hz, 1H), 7.46 (s, 1H), 7.52 (dd, J=7.8, 4.8 Hz, 2H), 8.02 (d, J=7.2 Hz, 1H), 8.68 (d, J=4.8 Hz, 1H). MS m/z 312.13[M+H]⁺.

TABLE 2 Selected data for compounds synthesised by Scheme 2. Compound Structure Spectral Data 34

¹H NMR (500 MHz, d6-DMSO) δ 2.93-2.96 (m, 2H), 3.15 (t, J = 6.0 Hz, 2H), 7.52 (dd, J = 7.8, 4.8 Hz, 1H), 7.56-7.60 (m, 4H), 7.61-7.65 (m, 1H), 7.92 (d, J = 7.2 Hz, 1H), 8.02 (d, J = 7.2 Hz, 1H). m/z 252.11 [M + H]⁺ 35

¹H NMR (600 MHz, d6-DMSO) δ 2.92-2.95 (m, 2H), 3.11 (t, J = 6.0 Hz, 2H), 4.02 (s, 3H), 7.12 (d, J = 7.2 Hz, 1H), 7.24 (d, J = 7.8 Hz, 1H), 7.35 (dd, J = 7.8, 4.8 Hz, 1H), 7.54-7.58 (m, 1H), 7.84 (d, J = 7.8 Hz, 1H), 7.93 (dd, J = 7.8, 1.2 Hz, 1H), 8.56 (d, J = 4.8 Hz, 1H). 36

¹H NMR (600 MHz, d6-DMSO) δ 2.92-2.95 (m, 2H), 3.16 (t, J = 6.0 Hz, 2H), 6.97 (t, J = 7.8 Hz, 1H), 7.05 (d, J = 7.8H, 1H), 7.23 (s, 1H), 7.42 (d, J = 6.6 Hz, 1H), 7.55 (s, 1H), 7.97 (d, J = 7.8 Hz, 1H), 8.07 (d, J = 6.6 Hz, 1H), 8.62 (d, J = 4.8 Hz, 1H), 11.25 (s, 1H), 11.78 (s, 1H). 37

¹H NMR (600 MHz, d6-DMSO) δ 1.49 (t, J = 7.2 Hz, 3H), 2.92 (t, J = 6.0 Hz, 2H), 3.12 (t, J = 6.0 Hz, 2H), 4.28 (q, J = 7.2 Hz, 2H), 7.11 (t, J = 7.8 Hz, 1H), 7.23 (d, J = 7.8 Hz, 1H), 7.35 (dd, J = 7.8, 4.8 Hz, 1H), 7.54 (t, J = 7.2 Hz, 1H), 7.83 (d, J = 7.2 Hz, 1H), 7.98 (dd, J = 7.8, 1.2 Hz, 1H), 8.56 (d, J = 4.8 Hz, 1H). m/z 296.14 [M + H]⁺.

The following 2-O-phenol substituted benzohydrazide derivatives were synthesised according to Scheme 3. Phenol intermediate E, synthesised using the procedure outlined in Scheme 1, was allowed to react with an alkyl halide in the presence of potassium carbonate to provide the required alkyl amino substituted ethers F.

Example 3 (E)-N′-(6,7-Dihydroquinolin-8(5H)-ylidene)-2-(2-(pyrrolidin-1-yl)ethoxy)benzohydrazide hydrochloride (41)

To a suspension of the (E)-N′-(6,7-dihydroquinolin-8(5H)-ylidene)-2-hydroxybenzohydrazide 12 (149 mg, 0.530 mmol) in dry DMF (10 mL) was added K₂CO₃ (246 mg, 1.78 mmol) and the chloroethylpyrrolidine hydrochloride (95 mg, 0.55 mmol). The reaction was heated to 45° C. for 2 days, then cooled to rt. The reaction was extracted into EtOAc (×3). Combined organic layers were washed with H₂O, brine, dried over Na₂SO₄, filtered and concentrated to afford a gummy brown solid. The residue was taken up in MeOH (7 mL) and treated with concentrated hydrochloric acid (0.3 mL). Solvent was removed in vacuo, the flask was cooled to rt, then ACN (5 mL) was added slowly. The flask was triturated and sonicated to provide (E)-N′-(6,7-dihydroquinolin-8(5H)-ylidene)-2-(2-(pyrrolidin-1-yl)ethoxy)benzohydrazide hydrochloride 41 as a fawn colored solid that was collected by filtration and dried at the pump. Yield 114 mg. ¹H NMR (500 MHz, d6-DMSO) δ 1.85-1.92 (m, 2H), 1.94-1.99 (m, 4H), 2.95 (t, J=6.0 Hz, 2H), 2.99-3.07 (m, 4H), 3.54-3.62 (m, 4H), 4.22-4.26 (m, 2H), 7.16 (t, J=7.8 Hz, 1H), 7.24 (d, J=7.8 Hz, 1H), 7.58 (t, J=7.2 Hz, 1H), 7.83 (s, 1H), 7.89 (s, 1H), 8.41 (br s, 1H), 8.67 (br s, 1H), 11.37 (s, 1H), 11.45 (br s, 1H). MS m/z 379.21 [M+H]⁺.

TABLE 3 Selected data for compounds according to Scheme 3 Mass Spec Compound Structure NMR Data [M + H]⁺ 39

¹H NMR (600 MHz, d6-DMSO) δ 1.97 (t, J = 6.0 Hz, 2H), 2.80 (s, 3H), 2.81 (s, 3H), 2.89 (t, J = 6.0 Hz, 2H), 3.00 (t, J = 6.0 Hz, 2H), 4.55 (s, 2H), 7.14 (t, J = 7.8 Hz, 1H), 7.26 J = 8.4 Hz, 1H), 7.57 (t, J = 7.2 Hz, 1H), 7.63 (d, J = 7.2 Hz, 1H), 7.96 (t, J = 7.2 Hz, 1H), 8.49 (d, J = 7.2 Hz, 1H), 8.71 (d, J = 4.2 Hz, 1H), 11.20 (br s, 1H), 11.42 (s, 1H). m/z 353.20 40

¹H NMR (600 MHz, d6-DMSO) δ 1.29-1.35 (m, 2H), 1.40-1.45 (m, 4H), 1.89 (t, J = 6.0 Hz, 2H), 2.63- 2.70 (m, 4H), 2.73 (t, J = 6.0 Hz, 2H), 2.78-2.84 (m, 4H), 4.34 (t, J = 6.0 Hz, 2H), 7.12 (t, J = 7.8 Hz, 1H), 7.28 (d, J = 7.8 Hz, 1H), 7.30- 7.33 (m, 1H), 7.53 (t, J = 8.4 Hz, 1H), 7.64 (d, J = 6.6 Hz, 1H), 7.99 (d, J = 6.6 Hz, 1H), 8.52 (d, J = 3.0 Hz, 1H), 10.94 (s, 1H). m/z 393.10 42

¹H NMR (600 MHz, d6-DMSO) δ 1.28-1.35 (m, 2H), 1.38-1.43 (m, 4H), 1.88 (t, J = 6.0 Hz, 2H), 1.97 (t, J = 6.0 Hz, 2H), 2.23-2.28 (m, 4H), 2.36 (t, J = 6.6 Hz, 2H), 2.70-2.78 (m, 4H), 4.23 (t, J = 6.6 Hz, 2H), 7.09 (t, J = 7.2 Hz, 1H), 7.92 (d, J = 7.2 Hz, 1H), 7.20 (d, J = 8.4 Hz, 1H), 7.29 (dd, J = 7.8, 4.8 Hz, 1H), 7.52 (t, J = 7.2 Hz, 1H), 7.62 (d, J = 7.2 Hz, 1H), 8.50 (d, J = 3.6 Hz, 1H), 10.83 (s, 1H). m/z 407.24

A range of acyl hydrazones can be prepared by the synthetic route depicted in Scheme 4. Heating an equimolar mixture of the 6-membered heterocyclic ketone G and the acylhydrazide in ethanol or other suitable solvent in the presence a catalytic amount of acid, furnished target acyl hydrazone compounds H (see table 4). The ketone starting materials were available from commercial suppliers or known literature methods.

Example 4 (E)-4-Methyl-N′-(1-(pyrimidin-2-yl)propylidene)-1,2,3-thiadiazole-5-carbohydrazide (43)

(Pyrimidin-2-yl)propan-1-one (114 mg) was heated together with 4-methyl-1,2,3-thiadiazole-5-carbohydrazide (132 mg) in EtOH (10 mL) in the presence of concentrated hydrochloric acid (one drop) to 60° C. for 30 min. The reaction was cooled to rt, then an off-white solid was collected by filtration. The crude product was further washed with ACN (×2) to generate (E)-4-methyl-N′-(1-(pyrimidin-2-yl)propylidene)-1,2,3-thiadiazole-5-carbohydrazide 43 (60 mg) as a white powder. ¹H NMR (600 MHz, d6-DMSO) δ 1.07 (t, J=7.2 Hz, 3H), 2.97 (s, 3H), 3.06 (q, J=7.2 Hz, 2H), 7.57 (t, J=6.6 Hz, 1H), 9.01 (d, J=6.6 Hz, 2H), 11.96 (s, 1H). MS m/z 277.0865 [M+H]⁺.

TABLE 4 MS Data for Compounds synthesised via Scheme 4 Mass Spectrometry Compound Structure [M + H]⁺ 44

m/z 269.1397 45

m/z 285.1347 46

m/z 285.1345 47

m/z 271.12  48

m/z 263.07  49

m/z 255.12  50

m/z 299.15  51

m/z 283.15  52

m/z 291.10  53

m/z 306.1399 54

m/z 269.1400 55

m/z 284.1393 56

m/z 276.0193 57

m/z 277.0856 58

m/z 269.1396 59

m/z 285.1354 60

m/z 297.0804 61

m/z 285.1344 62

m/z 305.1229 63

m/z 330.1435 64

m/z 284.1963 65

m/z 284.2141 66

m/z 312.2221 67

m/z 288.1760 68

m/z 297.2482 69

m/z 268.1961 70

m/z 296.1758 71

m/z 276.0914 72

m/z 310.0966 73

m/z 276.0913 74

m/z 268.1445 75

m/z 310.1210 197

m/z 296.0460

A range of substituted quinoline acyl hydrazones can be prepared by the synthetic route depicted in Scheme 5. Heating an equimolar mixture of acetyl quinoline I and substituted acylhydrazide in ethanol or other suitable solvent with a catalytic amount of acid, provided the target compounds J.

Example 5 (E)-N′-(1-(Quinolin-2-yl)ethylidene)picolinohydrazide (80)

2-Acetylquinoline (162 mg), pyridine-2-carboxylic acid hydrazide (113 mg) were heated together in EtOH (7 mL) at 60° C. One drop of concentrated hydrochloric acid was added and the reaction was stirred for 15 min at which time a precipitate formed. The reaction was cooled and the precipitate was collected by filtration to afford (E)-N′-(1-(quinolin-2-yl)ethylidene)picolinohydrazide 80 as an off-white powder (50 mg). ¹H NMR (600 MHz, d6-DMSO) δ 2.64 (s, 3H), 7.62-7.65 (m, 1H), 7.74-7.77 (m, 1H), 7.80 (t, J8.4 Hz, 1H), 8.02 (d, J=7.2 Hz, 1H), 8.07-8.11 (m, 2H), 8.19 (d, J=7.2 Hz, 1H), 8.33 (d, J=9. Hz, 1H), 8.43 (d, J=9.0 Hz, 1H), 8.76 (d, J=3.6 Hz, 1H), 11.26 (s, 1H). MS m/z 291.1321 [M+H]+.

TABLE 5 Selected data for compounds synthesised according to Scheme 5 Mass Compound Structure NMR Spec[M + H]⁺ 76

¹H NMR (600 MHz, d6-DMSO) δ 2.56 (s, 3H), 7.00 (t, J = 7.2 Hz, 1H), 7.11 (d, J = 7.2 Hz, 1H), 7.44 (d, J = 7.2 Hz, 1H) 7.64 (t, J = 7.2 Hz, 1H), 7.81 (t, J = 7.2 Hz, 1H), 8.02 (d, J = 7.8 Hz, 2H), 8.09 (d, J = 8.4 Hz, 1H), 8.32 (d, J = 8.4 Hz, 1H), 8.45 (d, J = 8.4 Hz, 1H), 11.61 (s, 1H). m/z 306.1399 77

¹H NMR (600 MHz, d6-DMSO) some peaks are not well resolved δ 2.61 (s, 3H), 3.83 (s, 3H), 3.84 (s, 3H), 7.09 (d, J = 8.4 Hz, 1H), 7.49 (s, 1H), 7.58 (d, J = 7.2 Hz, 1H), 7.61-7.65 (m, 1H), 7.80 (t, J = 7.8 Hz, 1H), 8.01 (d, J = 7.8 Hz, 1H), 8.08 (d, J = 8.4 Hz, 1H), 8.24 (s, 1H), 8.39-8.43 (m, 1H), 10.82 (br s, 1H). m/z 350.1635 78

¹H NMR (600 MHz, d6-DMSO) δ 2.60 (s, 3H), 3.86 (s, 3H), 7.18 (t, J = 8.4 Hz, 1H), 7.40-7.49 (m, 3H), 7.64 (t, J = 9.0 Hz, 1H), 7.80 (t, J = 9.0 Hz, 1H), 8.00 (d, J = 9.6 Hz, 1H), 8.09 (d, J = 9.6 Hz, 1H), 8.24- 8.38 (m, 1H), 8.42 (br s, 1H), 11.00 (s, 1H). m/z 320.1475 79

¹H NMR (500 MHz, d6-DMSO) δ 2.51 (s, 3H), 3.67 (s, 3H), 6.11 (t, J = 8.1 Hz, 2H), 6.64 (d, J = 7.5 Hz, 1H), 7.38 (d, J = 8.1 Hz, 1H), 7.57 (t, J = 8.4 Hz, 1H), 7.74 (t, J = 8.4 Hz, 1H), 7.95 (d, J = 8.1 Hz, 1H), 8.02 (d, J = 8.4 Hz, 1H), 8.32 (s, 2H) m/z 336.1578 80

¹H NMR (600 MHz, d6-DMSO) δ 2.64 (s, 3H), 7.62-7.65 (m, 1H), 7.74-7.77 (m, 1H), 7.80 (t, J = 8.4 Hz, 1H), 8.02 (d, J = 7.2 Hz, 1H), 8.07-8.11 (m, 2H), 8.19 (d, J = 7.2 Hz, 1H), 8.33 (d, J = 9. Hz, 1H), 8.43 (d, J = 9.0 Hz, 1H), 8.76 (d, J = 3.6 Hz, 1H), 11.26 (s, 1H). m/z 291.1321 81

¹H NMR (600 MHz, d6-DMSO) δ 2.41 (s, 3H), 2.60 (s, 3H), 7.40- 7.44 (m, 2H), 7.62-7.80 (m, 4H), 7.99 (s, 1H), 8.06 (d, J = 8.4 Hz, 1H), 8.26-8.34 (m, 1H), 8.40 (s, 1H), 10.98 (br s, 1H). m/z 304.1445 82

¹H NMR (600 MHz, d6-DMSO) δ 2.24 (s, 3H), 2.63 (s, 3H), 6.91 (t, J = 7.2 Hz, 1H), 7.38 (d, J = 6.6 Hz, 1H), 7.65 (t, J = 7.2 Hz, 1H), 7.81 (t, J = 7.2 Hz, 1H), 7.87 (s, 1H), 8.02 (d, J = 7.8 Hz, 1H), 8.35 (s, 1H), 8.43 (d, J = 7.8 Hz, 1H), ), 8.81 (d, J = 7.8 Hz, 1H), 11.39 (s, 1H). m/z 320.1531 83

¹H NMR (500 MHz, d6-DMSO) δ 1.37 (t, J = 7.2 Hz, 3H), 2.59 (s, 3H), 4.04 (q, J = 7.2 Hz, 2H), 7.11- 7.16 (m, 1H), 7.38-7.51 (m, 3H), 7.63 (d, J = 7.2 Hz. 1H), 7.78 (d, J = 7.2 Hz, 1H), 7.95-8.02 (m, 1H), 8.04-8.09 (m, 1H), 8.17-8.24 (m, 1H), 8.41-8.45 (m, 1H), 11.01 (br s, 1H). m/z 334.1549 84

¹H NMR (600 MHz, d6-DMSO) δ 2.55 (s, 3H), 2.66 (s, 3H), 2.68 (s, 3H), 7.62-7.65 (m, 1H), 7.77-7.81 (m, 1H), 7.99-8.06 (m, 2H), 8.25 (d, J = 8.4 Hz, 1H), 8.44 (d, J = 8.4 Hz, 1H), 11.02 (br s, 1H). m/z 325.1170 85

¹H NMR (600 MHz, d6-DMSO) δ 2.59 (s, 3H), 7.25 (dd, J = 6.6, 4.2 Hz, 1H), 7.62-7.65 (m, 1H), 7.77-7.81 (m, 1H), 7.98-8.09 (m, 4H), 8.32-8.36 (m, 1H), 8.41-8.44 (m, 1H), 11.40 (br s, 1H). m/z 296.0855 86

¹H NMR (600 MHz, d6-DMSO) δ 2.60 (s, 3H), 5.34 (s, 2H), 6.98 (d, J = 7.8 Hz, 1H), 7.04 (t, J = 7.8 Hz, 1H), 7.26 (t, J = 7.8 Hz, 1H), 7.48 (d, J = 6.6 Hz, 1H), 7.65 (t, J = 7.8 Hz, 1H), 7.81 (t, J = 7.8 Hz, 1H), 7.95 (s, 1H), 8.02 (d, J = 7.8 Hz, 1H), 8.08 (d, J = 7.8 Hz, 1H), 8.40 (br s, 1H), 8.53 (br s, 1H), 11.22 (br s, 1H). m/z 400.11  87

¹H NMR (600 MHz, d6-DMSO) δ 2.59 (s, 3H), 3.85 (s, 3H), 6.89 (d, J = 7.8 Hz, 1H), 7.44-7.48 (m, 2H), 7.64 (d, J = 8.4 Hz, 1H), 7.89 (d, J = 8.4 Hz, 1H), 7.99 (d, J = 7.2 Hz, 1H), 8.06 (d, J = 8.4 Hz, 1H), 8.22-8.27 (m, 1H), 8.39 (d, J = 8.4 Hz, 1H), 10.94 (s, 1H). m/z 336.1479 88

¹H NMR (600 MHz, d6-DMSO) δ 2.64 (s, 3H), 7.05-7.38 (br m, 2H), 7.44-7.51 (m, 2H), 7.66 (s, 1H), 7.81 (s, 1H), 8.02-8.10 (m, 3H), 8.39-8.47 (m, 2H), 11.37 (br s, 1H). m/z 346.1009 89

¹H NMR (600 MHz, d6-DMSO) major regioisomer δ 2.54 (s, 3H), 4.22 (s, 2H), 6.95 (t, J = 7.8 Hz, 1H), 7.02-7.06 (m, 1H), 7.24 (s, 1H), 7.32-7.36 (m, 1H), 7.58-7.63 (m, 2H), 7.79 (d, J = 7.8 Hz, 1H), 8.01 (d, J = 7.8 Hz, 1H), 8.08-8.14 (m, 1H), 8.35 (d, J = 7.8 Hz, 1H), 8.42 (s, 1H), 10.81 (s, 1H), 10.89 (s, 1H). m/z 343.1738 90

¹H NMR (600 MHz, d6-DMSO) δ 2.39 (s, 3H), 2.58 (s, 3H), 7.31- 7.36 (m, 2H), 7.59-7.63 (m, 1H), 7.77-7.91 (m, 3H), 7.95-8.03 (m, 2H), 8.24-8.40 (m, 2H), 10.87 (br s, 1H). m/z 304.1444 91

¹H NMR (600 MHz, d6-DMSO) δ 2.61 (s, 3H), 2.99 (s, 3H), 7.67 (d, J = 7.2 Hz, 1H), 7.81 (s, 1H), 8.02- 8.06 (m, 2H), 8.23 (d, J = 8.4 Hz, 1H), 8.53 (d, J = 8.4 Hz, 1H), 11.79 (s, 1H). m/z 312.0914 92

m/z 340.0848 160

m/z 334.1187 161

¹H NMR (500 MHz, d6-DMSO) δ 2.62 (s, 3H), 7.58 (t, J = 8.0 Hz, 1H), 7.64 (t, J = 7.0 Hz 1H), 7.68 (d, J = 8.0 Hz, 1H), 7.79 (t, J = 8.0 Hz, 1H), 7.89 (br s, 1H), 7.97 (br s, 1H), 8.00 (br s, 1H), 8.31 (br s, 1H), 8.41 (br s, 1H), 11.08 (s, 1H). m/z 324.0897 162

m/z 308.1191

A range of fused heterocyclic and heterocyclic substituted acyl hydrazones could be synthesised as outlined in Scheme 6. Starting ketone/aldehyde K is defined below in Scheme 6. Heating heterocyclic or fused heterocyclic ketone/aldehyde K with an appropriate ketohydrazide in the presence of catalytic acid and a suitable solvent provided the target compounds L.

Example 6 (E)-4-Methyl-N′-(1-(4-methylthiazol-2-yl)ethylidene)-1,2,3-thiadiazole-5-carbohydrazide (100)

4-Methyl-2-acetylthiazole (76 mg) was heated together with 4-methyl-1,2,3-thiadiazole-5-carbohydrazide (81 mg) in EtOH (7 mL) at 65° C. Concentrated hydrochloric acid (2 drops) were added and the reaction was heated for 1.5 h. After cooling to rt, a pale yellow solid precipitated out of solution and was collected by filtration to afford 100 (124 mg). ¹H NMR (600 MHz, d6-DMSO) δ 2.42 (s, 3H), 2.50 (s, 3H), 2.97 (s, 3H), 7.48 (s, 1H), 11.85 (s, 1H). MS m/z 282.0477[M+H]⁺.

TABLE 6 Selected data for compounds synthesised according to Scheme 6 Mass Spec Compound Structure NMR [M + H]⁺ 93

¹H NMR (600 MHz, d6-DMSO) δ 2.29 (s, 3H), 2.96 (s, 3H), 6.18 (s, 3H), 6.70 (s, 1H), 7.02 (s, 1H), 10.90 (s, 1H), 11.30 (s, 1H). m/z 250.0463 94

¹H NMR (600 MHz, d6-DMSO) δ 2.40 (s, 3H), 2.43 (s, 3H), 6.99 (s, 1H), 7.07 (d, J = 8.4 Hz, 1H), 7.36 (s, 1H), 7.44 (s, 1H), 7.98 (d, J = 7.2 Hz, 1H), 11.46 (s, 1H), 11.85 (s, 1H). m/z 276.0802 95

¹H NMR (600 MHz, d6-DMSO) δ 2.39 (s, 3H), 2.42 (s, 3H), 7.05 (d, J = 9.0 Hz, 1H), 7.37 (s, 1H), 7.46-7.49 (m, 1H), 7.89 (s, 1H), 11.42 (s, 1H), 12.03 (br s, 1H). m/z 310.12 96

¹H NMR (600 MHz, d6-DMSO) δ 2.44 (s, 3H), 2.55 (s, 3H), 3.86 (s, 3H), 6.94 (d, J = 8.4 Hz, 1H), 7.30-7.34 (m, 2H), 7.68 (s, 1H), 9.87 (s, 1H). m/z 306.0906 97

¹H NMR (600 MHz, d6-DMSO) δ 2.37 (s, 3H), 2.41 (s, 3H), 7.38- 7.52 (m, 3H), 8.02 (d, J = 7.8 Hz, 1H), 8.05 (d, J = 7.8 Hz, 1H), 8.41 (s, 1H). m/z 316.0591 98

¹H NMR (600 MHz, d6-DMSO) δ 2.41 (s, 3H), 2.48 (s, 3H), 3.00 (s, 6H), 6.80 (d, J = 9.0 Hz, 2H), 7.67 (s, 1H), 7.77 (d, J = 9.0 Hz, 2H). m/z 303.1273 99

¹H NMR (600 MHz, d6-DMSO) δ 2.45 (s, 3H), 2.58 (s, 3H), 3.85 (s, 3H), 3.86 (s, 3H),7.16(d, J = 8.4 Hz, 1H), 7.46 (s, 1H), 7.53 (t, J = 8.4 Hz, 1H), 7.70 (s, 1H). m/z 320.1061 100

¹H NMR (600 MHz, d6-DMSO) δ 2.42 (s, 3H), 2.50 (s, 3H), 2.97 (s, 3H), 7.48 (s, 1H), 11.85 (s, 1H). m/z 282.0477 101

¹H NMR (600 MHz, d6-DMSO) δ 2.40 (s, 3H), 2.44 (s, 3H), 5.31 (s, 2H), 6.97 (dd, J = 6.6, 9.6 Hz, 1H), 7.03 (dt, J = 1.8, 9.0 Hz, 1H), 7.24-7.28 (m, 1H), 7.40-7.44 (m, 2H), 7.88 (s, 1H), 10.74 (br s, 1H). m/z 370.0680 102

¹H NMR (600 MHz, d6-DMSO) δ 2.36 (s, 3H), 2.46 (s, 3H), 2.96 (s, 3H), 6.85 (d, J = 3.6 Hz, 1H), 7.41 (d, J = 3.6 Hz, 1H), 11.48 (s, 1H). m/z 281.05 103

¹H NMR (600 MHz, d6-DMSO) δ 2.29 (s, 3H), 2.33 (s, 3H), 2.45 (s, 3H), 6.81-6.86 (m, 2H), 7.32- 7.37 (m, 2H), 7.76 (d, J = 9.6 Hz, 1H), 11.05 (s, 1H), 12.17 (br s, 1H). m/z 289.1008 104

¹H NMR (600 MHz, d6-DMSO) δ 2.52 (s, 3H), 6.99-7.07 (m, 2H), 7.44-7.53 (m, 3H), 7.99-8.12 (m, 3H), 11.62 (s, 1H), 11.81 (s, 1H). m/z 312.0857 105

¹H NMR (600 MHz, d6-DMSO) δ 2.23 (s, 3H), 2.59 (s, 3H), 6.91 (t,J = 7.8 Hz, 1H), 7.38(d, J = 6.6 Hz, 1H), 7.48-7.56 (m, 2H), 7.82 (s, 1H), 8.05 (d, J = 7.8 Hz, 1H), 8.12 (d, J = 7.8 Hz, 1H), 11.47 (s, 1H), 11.58 (brs, 1H). m/z 326.0958 106

¹H NMR (600 MHz, d6-DMSO) δ 2.20 (s, 3H), 2.37 (s, 3H), 2.51 (s, 3H), 7.41 (d, J = 4.2 Hz, 2H), 7.68-7.72 (m, 2H), 8.55 (s, 1H), 12.08 (s, 1H). m/z 274.1007 107

¹H NMR (600 MHz, d6-DMSO) δ 2.28 (s, 3H), 2.37 (s, 3H), 3.82 (s, 3H), 7.17 (d, J = 7.2 Hz, 1H), 7.40-7.46 (m, 3H), 8.52 (s, 1H), 12.01 (s, 1H). mz 290.0955 108

m/z 248.0517 109

¹H NMR (600 MHz, d6-DMSO) δ 7.01 (d, J = 8.4 Hz, 1H), 7.46 (dd, J = 8.4, 2.4 Hz, 1H), 7.81 (d, J = 2.4 Hz, 1H), 7.87 (s, 1H), 7.98 (d, J = 2.4 Hz, 1H), 8.65 (s, 1H), 11.55 (brs, 1H), 12.06 (s, 1H). m/z 282.0982 110

¹H NMR (600 MHz, d6-DMSO) δ 3.96 (s, 3H), 6.93 (d, J = 8.4 Hz, 2H), 6.96 (s, 1H), 7.35 (s, 1H), 7.40-7.45 (m, 1H), 7.84 (d, J = 5.4 Hz, 1H), 8.41 (s, 1H), 11.92 (s, 1H). m/z 245.1050 111

¹H NMR (600 MHz, d6-DMSO) δ 2.17 (s, 3H), 4.00 (s, 3H), 6.80 (t, J = 7.8 Hz, 1H), 7.19 (s, 1H), 7.37 (d, J = 7.2 Hz, 1H), 7.47 (s, 1H), 7.62 (d, J = 7.2 Hz, 1H), 8.56 (s, 1H). m/z 259.1179 112

¹H NMR (600 MHz, d6-DMSO) δ 2.39 (s, 3H), 4.00 (s, 3H), 7.4 (d, J = 7.8 Hz, 2H), 7.71 (s, 1H), 7.80- 7.85 (m, 3H), 8.80 (s, 1H), 12.88 (br s, 1H). m/z 243.1241 113

¹H NMR (600 MHz, d6-DMSO) δ 3.96 (s, 3H), 6.99 (d, J = 9.O Hz, 1H), 7.06 (s, 1H), 7.36 (s, 1H), 7.45 (dd, J = 9.0, 2.4 Hz, 1H), 7.86 (d, J = 2.4 Hz, 1H), 8.40 (s, 1H). m/z 279.0651 114

¹H NMR (600 MHz, d6-DMSO) δ 6.96-7.01 (m, 2H), 7.44-7.55 (m, 3H), 7.82 (d, J = 1.2 Hz, 1H), 8.05 (d, J = 7.2 Hz, 1H), 8.15 (d, J = 7.2 Hz, 1H), 8.77 (s, 1H), 11.41 (s, 1H), 12.42 (s, 1H). m/z 298.0686 115

¹H NMR (600 MHz, d6-DMSO) δ 7.03 (d, J = 9.0 Hz, 1H), 7.47-7.56 (m, 3H), 7.81 (d, J = 3.0 Hz, 1H), 7.96 (d, J = 7.8 Hz, 1H), 8.15 (d, J = 7.8 Hz, 1H), 8.74 (s, 1H), 11.43 (br s, 1H), 12.22 (s, 1H). m/z 332.0253 116

¹H NMR (600 MHz, d6-DMSO) δ 4.02 (s, 3H), 7.70-7.74 (m, 2H), 7.77 (s,lH), 8.06-8.15 (m, 2H), 8.74 (d, J = 7.2 Hz, 1H), 8.85 (s, 1H), 12.97 (s, 1H). m/z 230.1032 117

¹H NMR (600 MHz, d6-DMSO) δ 2.58 (s, 3H), 4.02(s, 3H), 7.69 (d, J = 6.6 Hz, 1H), 7.67 (s, 1H), 7.79 (s, 1H), 8.30 (s, 1H), 8.73 (s, 1H), 9.06 (s, 1H), 12.97 (s, 1H). m/z 244.1193 118

¹H NMR (600 MHz, d6-DMSO) δ 7.68 (t,J = 8.4 Hz, 1H), 7.85 (s, 1H), 7.95 (s, 1H), 8.06 (t, J = 7.2 Hz, 1H), 8.13 (d, J = 7.2 Hz, 1H), 8.72 (d,./ 2.4 Hz. 1H), 8.88 (s, 1H), 12.62 (s, 1H). m/z 233.0492 119

¹H NMR (600 MHz, d6-DMSO) δ 2.17(s, 3H), 6.87 (t, J = 9.O Hz, 1H), 7.39 (d, J = 7.2 Hz, 1H), 7.88 (dd, J = 13.2, 8.4 Hz, 1H), 7.98 (s, 1H), 8.80 (s, 1H), 12.39 (brs, 1H), 12.46 (s, 1H). m/z 262.0646 163

m/z 230.1034 164

m/z 273.1346 165

¹H NMR (500 MHz, d6-DMSO) δ 4.01 (s, 3H), 7.56-7.62 (m, 1H), 7.70-7.74 (m, 2H), 7.83 (br s, 1H), 7.96-8.00 (m, 1H), 8.07 (s, 1H), 8.77 (s, 1H), 13.01 (s, 1H). m/z 263.0692 166

¹H NMR (500 MHz, d6-DMSO) δ 3.97 (s, 3H), 7.24 (t, J = 4.5 Hz, 1H), 7.42 (s, 1H), 7.59 (s, 1H), 7.93 (d, J = 4.5 Hz, 1H), 8.04 (s, 1H), 8.58 (s, 1H), 12.51 (s, 1H). m/z 235.06 167

¹H NMR (500 MHz, d6-DMSO) δ 2.48 (s, 3H), 3.94 (s, 3H), 6.67 (s, 1H), 7.24 (s, 1H), 7.48 (s, 1H), 8.51 (s, 1H), 12.47 (s, 1H). m/z 234.10 168

m/z 251.0709 169

m/z 273.0980

Similarly, imidazopyridine derivatives were synthesised according to Scheme 7.

Example 7 (Z)—N′-(Imidazo[1,2-a]pyridin-2-ylmethylene)-3-methoxybenzohydrazide (120)

Imidiazo[1,2-a]pyridine-2-carboxaldehyde (101 mg) and 3-methoxybenzohydrazide (114 mg) were heated to reflux in EtOH (7 mL) in the presence of concentrated hydrochloric acid for 2 h. The reaction was allowed to cool and the resulting white precipitate was collected by filtration to afford (Z)—N′-(imidazo[1,2-a]pyridin-2-ylmethylene)-3-methoxybenzohydrazide 120 (61 mg) as an off-white solid. ¹H NMR (600 MHz, d6-DMSO) δ 3.85 (s, 3H), 7.19 (dd, J=8.4, 2.4 Hz, 1H), 7.44-7.48 (m, 2H), 7.56-7.60 (m, 2H), 7.85 (d, J=3.0 Hz, 1H), 7.93 (t, J=7.8 Hz, 1H), 8.73 (s, 1H), 8.89 (d, J=6.0 Hz, 1H), 8.91 (s, 1H), 12.62 (s, 1H). MS m/z 295.1191[M+H]⁺.

TABLE 7 NMR and MS Data for compounds synthesised via Scheme 7. Mass Spec Compound Structure NMR [M + H]⁺ 121

¹H NMR (600 MHz, d6-DMSO) δ 2.39 (s, 3H), 7.42-7.49 (m, 3H), 7.80-7.86 (m, 3H), 7.94 (t, J = 7.8 Hz, 1H), 8.72-8.76 (m, 2H), 8.91 (d, J = 6.6 Hz, 1H), 12.56 (s, 1H). m/z 279.1242 138

¹H NMR (600 MHz, d6-DMSO) δ 7.42-7.53 (m, 3H), 7.86 (br s, 1H), 7.92 (s, 1H), 8.00-8.08 (m, 2H), 8.46 (s, 1H), 8.74 (s, 1H), 8.90 (d, J = 6.0 Hz, 1H), 11.98 (br s, 1H), 12.90 (s, 1H). m/z 321.1164 139

¹H NMR (600 MHz, d6-DMSO) δ 6.94-7.03 (m, 3H), 7.35-7.45 (m, 2H), 7.61 (d,J = 9.0 Hz, 1H), 7.88 (d, J = 7.2 Hz, 1H),8.41 (s, 1H), 8.54 (s, 1H), 8.61 (d, J = 3.6 Hz, 1H), 11.81 (s, 1H), 11.96 (s, 1H). m/z 281.1391

A variety of dipyridyl acyl hydrazones were synthesised according to Scheme 8. Dimethyldipyridyl ketone O was heated together with substituted arylbenzhydrazides to afford target acyl hydrazones P.

Example 8 N′-(bis(6-Methylpyridin-2-yl)methylene)-4-hydroxy-3-methoxybenzohydrazide (130)

Bis(6-methylpyridin-2-yl)methanone (227 mg) and vanillic acid hydrazide (195 mg) in EtOH (10 mL) were treated with 2 drops of concentrated hydrochloric acid and the reaction was heated to 60° C. for 1 h. The reaction was allowed to cool and a yellow solid was collected by filtration to afford N′-(bis(6-methylpyridin-2-yl)methylene)-4-hydroxy-3-methoxybenzohydrazide 130 (248 mg) as a beige solid. ¹H NMR (600 MHz, d6-DMSO) δ 2.61 (s, 3H), 2.70 (s, 3H), 3.84 (s, 3H), 6.98 (d, J=8.4 Hz, 1H), 7.31 (d, J=8.4 Hz, 1H), 7.41-7.45 (m, 2H), 7.55 (d, J=7.8 Hz, 1H), 7.64 (s, 1H), 7.83 (d, J=7.8 Hz, 1H), 7.97 (d, J=7.8 Hz, 1H), 8.16 (s, 1H), 10.02 (br s, 1H), 15.25 (br s, 1H). MS m/z 377.1611[M+H]⁺.

In a further example, a phenolic hydrazone derivative 184 could be converted to the dimethylaminomethyl compound 185 by the action of tetramethylenediamine in refluxing toluene (see example 8a below).

Example 8a 5-chloro-N′-(di(pyridin-2-yl)methylene)-3-((dimethylamino)methyl)-2-hydroxybenzohydrazide (185)

5-chloro-N′-(di(pyridin-2-yl)methylene)-2-hydroxybenzohydrazide 184 (801 mg, 2.27 mmol) was suspended in toluene (95 mL) and treated with N, N, N, N,-tetramethylenediamine (4 mL). The reaction was heated to reflux for 4 h, then allowed to cool to rt o/n. Volatiles were removed in vacuo and the resulting residue was taken up in acetonitrile (4 mL) then ether (20 mL) was added slowly. The resulting precipitate was collected by filtration to afford 5-chloro-N′-(di(pyridin-2-yl)methylene)-3-((dimethylamino)methyl)-2-hydroxybenzohydrazide (747 mg) as a yellow solid. ¹H NMR (600 MHz, d6-DMSO) δ 2.60 (s, 6H), 3.98 (s, 2H), 7.12 (s, 1H), 7.37-7.43 (m, 2H), 7.51 (d, J=6.0 Hz, 1H), 7.69 (s, 1H), 7.90-7.94 (m, 2H), 8.14 (d, J=9.6 Hz, 1H), 8.46 (s, 1H), 8.76-8.78 (m, 1H), 8.60 (br s, 1H), 8.76 (14.48 (s, 1H). MS m/z 410.2014[M+H]⁺.

TABLE 8 MS Data for compounds synthesised according to Scheme 8 Mass Com- Spectrometry pound Structure [M + H]⁺ 122

m/z 345.1892 123

m/z 374.18 124

m/z 359.27 125

m/z 359.19 126

m/z 391.1913 127

m/z 347.1744 128

m/z 381.1627 129

m/z 361.1789 131

m/z 361.1160 132

m/z 375.1816 133

m/z 345.17 134

m/z 349.1459 135

m/z 332.1506 136

m/z 336.1455 137

m/z 366.1384 140

m/z 399.1429 141

m/z 345.17 142

m/z 387.1275 143

m/z 332.1993 144

m/z 361.1660 154

m/z 321.1346 155

m/z 346.1666 181

m/z 375.1451 182

m/z 353.1181 183

m/z 332.1506 184

m/z 381.1627 185

m/z 410.2014 186

m/z 325.1081 187

m/z 363.1684 188

m/z 317.1400 189

m/z 333.1347 190

m/z 349.1296 191

m/z 361.1661

Acrylonitrile derivatives could be synthesised as outlined in Scheme 9 below

Quinolone ketone could be converted to the acetocyanohydrazide Q by allowing to react with 2-cyanoacetohydrazide under standard conditions. Intermediate Q is then allowed to react with an aldehyde in the presence of catalytic piperidine to afford the required acrylonitrile derivative R.

Synthesis of (E)-2-cyano-N′-(6,7-dihydroquinolin-8(5H)-ylidene)acetohydrazide

To a mixture of 6,7 dihydroquinolin-8-one (906 mg) Q (R₁, R₂=fused quinoline), acetocyanohydrazide (712 mg) in EtOH (40 mL) was added conc. hydrochloric acid (3 drops) and the reaction was heated to 50° C. for 1 h. After cooling to rt, (E)-2-cyano-N′-(6,7-dihydroquinolin-8(5H)-ylidene)acetohydrazide R (R₁, R₂=fused quinoline) precipitated out of solution as a tan solid. The solid was collected by filtration and dried at the pump to afford 1.2 g of material. MS m/z 229.1081 [M+H]⁺.

Example 9 (2E,N′E)-2-Cyano-N′-(6,7-dihydroquinolin-8(5H)-ylidene)-3-(2-hydroxyphenyl) acrylohydrazide 145

To a mixture of the (E)-2-cyano-N′-(6,7-dihydroquinolin-8(5H)-ylidene)acetohydrazide (70 mg) R (179) in EtOH (8 mL) was added salicylaldehyde (110 μL). This was followed by the addition of a 0.1M solution of piperidine in EtOH (0.2 mL) with vigorous stirring at room temp and gentle heating to get all into solution. After 30 min, a pale yellow solid was collected by filtration and washed with EtOH (×3). After drying 17 mg of (2E,N′E)-2-cyano-N′-(6,7-dihydroquinolin-8(5H)-ylidene)-3-(2-hydroxyphenyl)acrylohydrazide S (145) was obtained. ¹H NMR (600 MHz, d6-DMSO) δ 1.89 (t, J=6.0 Hz, 2H), 2.70 (t, J=6.0 Hz, 2H), 2.80 (t, J=6.0 Hz, 2H), 7.24-7.31 (m, 3H), 7.58 (dt, J=8.4, 1.2 Hz, 1H), 7.62 (d, J=8.4 Hz, 1H), 7.82 (dd, J=7.8, 1.2 Hz, 1H), 8.50 (dd, J=4.8, 1.2 Hz, 1H), 8.64 (s, 1H), 9.27 (s, 1H), 13.53 (s, 1H). MS m/z 333.1347 [M+H]⁺.

TABLE 9 Selected data for compounds synthesised according to Scheme 9 Mass Spec Compound Structure NMR [M + H]⁺ 170

¹H NMR (500 MHz, d6-DMSO) δ 1.91 (t, J = 6.0 Hz, 2H), 2.72 (t, J = 6.0 Hz, 2H), 2.82 (t, J = 6.0 Hz, 2H), 7.29-7.34 (m, 2H), 7.45 (dt, J = 8.5, 3.0 Hz, 2H), 7.65 (d, J = 7.5 Hz, 1H), 7.74 (dd, J = 8.5, 3.0 Hz), 8.53 (d, J = 3.5 Hz, 1H), 8.64 (s, 1H), 9.37 (s, 1H), 13.51 (s, 1H). m/z 351.1251 179 (R)

m/z 229.1081 192

m/z 294.1439 193

¹H NMR (600 MHz, d6-DMSO) δ 2.44 (s, 3H), 2.71 (s, 3H), 3.81 (s, 3H), 4.33 (s, 1H), 6.94 (d, J = 8.4 Hz, 1H), 7.19 (d, J = 7.2 Hz, 1H), 7.34 (d, J = 7.2 Hz, 1H), 7.44 (d, J = 7.2 Hz, 1H), 7.60-7.64 (m, 2H), 7.75 (s, 1H), 7.82-7.87 (m, 2H), 8.31 (s, 1H). m/z 428.1271 194

¹H NMR (600 MHz, d6-DMSO) δ 2.47 (s, 3H), 2.71 (s, 3H), 3.92 (s, 3H), 7.15 (t, J = 7.8 Hz, 1H), 7.23 (t, J = 4.2 Hz, 2H), 7.37 (d, J = 7.8 Hz, 1H), 7.47 (d, J = 7.8 Hz, 1H), 7.61- 7.65 (m, 2H), 7.84-7.89 (m, 2H), 8.65 (s, 1H). m/z 412.1774 195

¹H NMR (600 MHz, d6-DMSO) δ 7.51-7.57 (m, 2H), 7.57-7.60 (m, 1H), 7.63-7.66 (m, 1H), 7.92 (d, J = 7.8 Hz, 1H), 7.96 (d, J = 7.8 Hz, 1H), 7.99-8.05 (m, 3H), 8.47 (s, 1H), 8.65 (d, J = 4.8 Hz, 1H), 8.80 (t, J = 4.8 Hz, 2H). m/z 355.1303 196

¹H NMR (600 MHz, d6-DMSO) δ 2.50 (s, 3H), 3.83 (s, 3H), 6.95 (d, J = 8.4 Hz, 1H), 7.59-7.63 (m, 2H), 7.77 (s, 1H), 7.85 (d, J = 8.4 Hz, 1H), 8.13 (t,J = 7.8 Hz, 1H), 8.29 (s, 1H), 8.71 (d, J = 3.6 Hz, 1H), 10.4 (br s, 1H). m/z 337.1296

In a further example, substitution of the hydrazide group could be achieved by allowing an acyl hydrazone compound to react with a substituted alkyl halide in the presence of potassium carbonate to generate compounds U as described in Scheme 10 below. Heating 2-acetylpyridine with a substituted hydrazide afforded acyl hydrazone T. Alkylation of T by the action of a methyl bromoacetate and potassium carbonate in DMF generated ester U. In addition, compound U could be readily hydrolysed to a carboxylic acid derivative V by reaction with lithium hydroxide in a mixture of THF and water.

Example 10 (E)-N′-(1-(Pyridin-2-yl)ethylidene)benzo[b]thiophene-2-carbohydrazide (146)

To a mixture of 2-acetylpyridine (326 mg), benzothiophene-2-carboxylic acid hydrazide (518 mg) in EtOH (15 mL) at 60° C. was added 3 drops of conc. HCl. After heating for 30 min, the reaction was cooled overnight and a white solid precipitated out of solution to provide (E)-N′-(1-(pyridin-2-yl)ethylidene)benzo[b]thiophene-2-carbohydrazide (650 mg). MS m/z 296.0460[M+H]⁺.

TABLE 10 Hydrazone Intermediates synthesized according to Scheme 10 Compound Structure Spectroscopic Data 152

¹H NMR (600 MHz, d6-DMSO) δ 2.45 (s, 3H), 2.97 (s, 3H), 7.47- 7.50 (m, 1H), 7.98 (t, J = 7.8 Hz, 1H), 8.06 (d, 7=7.8 Hz, 1H), 8.65 (d, J = 3.6 Hz, 1H), 11.7 (s, 1H). MS mz 262.087 [M + H]⁺. 153

¹H NMR (600 MHz, d6-DMSO) δ 2.97 (s, 3H), 7.69 (dd,J = 6.6, 4.8 Hz, 1H), 8.01 (s, 1H), 8.11 (d, J = 8.4 Hz, 1H), 8.25 (s, 1H), 8.66 (d, J = 4.2 Hz, 1H), 12.59 (s, 1H)

(E)-Methyl 2-(1-(benzo[b]thiophene-2-carbonyl)-2-(1-(pyridin-2-yl) ethylidene) hydrazinyl) Acetate 147

To a solution of (E)-N′-(1-(pyridin-2-yl)ethylidene)benzo[b]thiophene-2-carbohydrazide (190 mg) in DMF (8 mL) was added methyl bromoacetate (200 μL) and K₂CO₃ (210 mg). The reaction was heated to 50° C. for 1.5 h during which time a white precipitate formed. The reaction was cooled, and H₂O (8 mL) was added slowly. After allowing to stand for 30 min, (E)-methyl 2-(1-(benzo[b]thiophene-2-carbonyl)-2-(1-(pyridin-2-yl) ethylidene)hydrazinyl)acetate precipitated out of solution as a yellow solid (90 mg) 147. ¹H NMR (d6-DMSO) δ 2.44 (s, 3H), 3.73 (s, 3H), 5.06 (s, 2H), 7.44-7.49 (m, 2H), 7.53 (d, J=7.2 Hz, 1H), 8.00-8.06 (m, 3H), 8.21 (s, 1H), 8.41 (d, J=7.8 Hz, 1H), 8.69 (d, J=3.6 Hz, 1H). MS m/z 368.1061 [M+H]⁺.

(E)-2-(1-(Benzo[b]thiophene-2-carbonyl)-2-(1-(pyridin-2-yl)ethylidene)hydrazinyl) acetic acid 148

To a solution of (E)-methyl 2-(1-(benzo[b]thiophene-2-carbonyl)-2-(1-(pyridin-2-yl) ethylidene)hydrazinyl) acetate (64 mg) in THF (7 mL) was added LiOH (65 mg) and H₂O (3 mL). The reaction was heated to 50° C. for 2 h and then cooled to rt. THF was removed in vacuo and a yellow precipitate formed. The product was collected by filtration to afford (E)-2-(1-(benzo[b]thiophene-2-carbonyl)-2-(1-(pyridin-2-yl)ethylidene) hydrazinyl)acetic acid as a yellow powder. MS m/z 354.09 [M+H]⁺.

TABLE 11 Target compounds prepared according to Scheme 10. Compound Structure Spectroscopic Data 149

¹H NMR (600 MHz, d6-DMSO) 8 2.50 (s, 3H), 2.99 (s, 3H), 3.74 (s, 3H), 5.14 (s, 2H), 7.55 (dd, J = 7.2, 4.8 Hz, 1H), 8.04 (t, J = 7.8 Hz, 1H), 8.24 (d, J = 7.8 Hz, 1H), 8.71 (d, J = 4.8 Hz, 1H). MS m/z 334.0996 [M + H]⁺. 150

¹H NMR (600 MHz, d6-DMSO) 8 2.98 (s, 3H), 3.77 (s, 3H), 5.15 (s, 2H), 7.48- 7.52 (m, 1H), 8.01-8.09 (m, 2H), 8.20 (s, 1H), 8.74-8.78 (m, 1H). MS m/z 320.0822 [M + H]⁺. 151

H NMR (600 MHz, d6-DMSO) 8 2.51 (s, 3H), 2.98 (s, 3H), 5.05 (s, 2H), 7.54- 7.57 (m, 1H), 8.05 (t, J = 7.2 Hz, 1H), 8.25 (d, J = 7.8 Hz, 1H), 8.71 (d,J = 3.6 Hz, 1H). MS m/z 320.08 [M + H]⁺.

In a further example, a number fused pyridopyrano acyl hydrazones were synthesised according to Scheme 11. ketone V was heated together with substituted aryl benzhydrazides in the presence of catalytic acid to afford target acyl hydrazones W.

Example 11 (E)-N′-(2,3-dihydro-4H-pyrano[3,2-b]pyridin-4-ylidene)nicotinohydrazide (171)

To a mixture of 2H-pyran[3,2-b]pyridine-4(3H)-one V (49 mg, 0.33 mmol) in EtOH (6 mL) was added nicotinic acid hydrazide (44 mg, 0.32 mmol) followed by one drop of conc. HCl. The reaction was heated to 55° C. for 30 min, then cooled to room temp to afford (E)-N′-(2,3-dihydro-4H-pyrano[3,2-b]pyridin-4-ylidene)nicotinohydrazide 171 as an off-white solid. (34 mg). ¹H NMR (500 MHz, d6-DMSO) δ 2.96 (t, J=6.0 Hz, 2H), 4.47 (t, J=6.0 Hz, 2H), 7.56-7.64 (m, 2H), 7.77 (t, J=5.0 Hz, 1H), 8.41 (d, J=7.5 Hz, 1H), 8.50 (d, J=5 Hz, 1H), 8.88 (d, J=5.0 Hz, 1H), 9.13 (s, 1H), 15.63 (s, 1H). MS: m/z 269.1033 [M+H]+.

TABLE 12 Compounds synthesized according to Scheme 11 Mass Spectrometry Compound Structure [M + H]⁺ 172

m/z 290.0708 173

m/z 298.1189 174

m/z 302.0692 175

m/z 303.0911 176

m/z 282.1236 177

m/z 284.1027 178

m/z 274.0646

BIOLOGICAL EXAMPLES

GSK 3b Assay

The phosphorylation of GSK-3β is enhanced when Zn is imported into a cell by a Zn ionophore. This property was measured for the compounds of the current invention and the data presented relative to the know Zn ionophore PBT2 using the following protocol.

The human neuroblastoma SH-SY5Y cells were obtained from Cell bank Australia (Catalogue number: 94030304). SH-SY5Y cell culture was maintained in DMEM/F12+15% FBS inside an incubator at 37° C. in the presence of 5% CO₂. The cells were sub-cultured once a week and the media exchanged once during the week. Cells for the assay were plated at a density of 60,000 cells/well.

Stock solutions of the samples were prepared as a 5 mM stock in DMSO and a stock solution of 1 mM ZnCl₂/3 mM Glutamic acid was prepared in water. Immediately before use the compounds were diluted 1:10 with water before being added to Locke's buffer in a treatment tube. Samples were subsequently treated with either distilled water or the ZnCl₂/Glutamic acid solution to yield a treatment solution which has a final concentration of the test compound at 2 μM+/−ZnCl₂ at 5 μM.

The culture media was aspirated from the wells and the media replaced with the treatment solution prepared above. In addition to the relative standard (PBT2+/−ZnCl₂), control wells were also included consisting of +/−ZnCl₂ at 5 μM with all treatments done in triplicate. The plate was incubated at 37° C. with the treatment solution for 2 h after which time the wells were aspirated and washed with sterile PBS.

Measurement of the change of phospho-GSK-3β was determined using an AlphaScreen® SureFire® Phospho-GSK 30β (Ser9) Kit with the cells being processed as per the manufacturer's instructions using an initial incubation of 2 h/24° C. and a final incubation of 16 h/24° C.

The fluorescence was measured on an Enspire plate reader. In the absence of the metal, the compounds had no effect on the signal whereas, in the presence of the metal, positive compounds showed an increased signal which is presented as a % of the positive standard PBT2+ZnCl₂ set as 10000. Representative data is presented in Table 12 using the following ranges: A<50%, B 50-<100%, C 100-<150%, D>150%.

TABLE 12 GSK Data for Selected Compounds Compound GSK-Zn Compound GSK-Zn Compound GSK-Zn  1 A 43 C  92 C  2 A 44 B  94 C  3 A 45 C  95 C  4 A 46 C 100 C  6 A 47 C 103 B  7 A 48 C 104 D  8 A 49 B 105 B  9 A 50 C 106 A 10 B 51 B 109 B 11 C 52 B 115 A 12 B 64 B 119 A 15 D 65 B 121 A 16 A 67 C 122 A 17 A 72 C 123 C 18 B 73 C 126 C 20 A 74 B 128 D 21 A 75 C 129 C 23 C 76 C 130 A 24 A 77 C 131 B 25 B 78 C 132 C 26 A 81 C 133 C 38 A 82 C 134 B 39 A 87 C 135 B 41 A 91 C 146 C

Method I: Measurement of Fe Efflux from Cells

Compounds of the current invention were assessed for their ability to efflux iron (Fe) from a cell using the following protocol.

The human neuroblastoma line BE(2)-M17 (M17) cell cultures were acquired from Sigma Aldrich (Catalogue #: 95011816). M17 Cells were maintained in Opti-MEM reduced serum media supplemented with 10% fetal bovine serum (Bovogen, SFBSF) and passaged twice weekly. Cells were cultured at 37° C. in the presence of 5% CO₂. Culture supplies were sourced from Thermo Fisher unless otherwise stated.

A solution of ⁵⁷Fe cold isotope was prepared by dissolving ⁵⁷Fe metal (>95% enrichment, Trace Sciences International) in concentrated HCl to give a final concentration of 573 mM. From this master solution, a 10 mM working solution was prepared in sterile water. The working solution was used within two months of preparation.

M17 cells were loaded with iron initially by seeding into 48-well plates at a density of 0.15×10⁶ cells per well in 0.5 mL media. After 48 h, old media was discarded. Fresh media was supplemented with 20 μM ⁵⁷Fe isotope, from the 10 mM ⁵⁷Fe working solution. Cells received 0.2 mL of this ⁵⁷Fe enriched media and were returned to the incubator for 20 h. The ability of experimental compounds to efflux iron was determined by the dissolution of compounds in DMSO and diluted in Hanks' Balanced Salt Solution (HBSS) for treatment of M17 cells. After ⁵⁷Fe incubation, cells were rinsed twice with HBSS and treated with 0.15 mL trial compound for 2 h at a concentration of 20 μM. All assays included a relevant vehicle (0.4%-0.8% DMSO) as well as a positive control (20 μM). Following the treatment period, 0.1 mL of media was collected from cells and the extracellular ⁵⁷Fe content was analysed via inductively coupled mass spectrometry (ICP-MS, Agilent 7700x series instrument).

To perform this protocol the following supplies were purchased from Sigma Aldrich: anhydrous dimethyl sulfoxide (DMSO, Catalogue #: 276855), Hanks' Balanced Salt Solution supplemented with 20 mM HEPES and 4.2 mM Sodium Bicarbonate (HBSS, pH: 7.4, Catalogue #: H1387).

The ability of the compounds of the invention to efflux Fe from a cell was determined using the above protocol hence cells having been pre-treated with Fe in the media for 24 h were subsequently washed and treated with fresh, Fe free media either with or without the compound (20 μM). After 2 h the Fe levels in the media were measured and the increase determined as a percentage increase relative to the cell media in the absence of the compound.

${\%{Fe}{efflux}} = {\frac{\left( {\left\lbrack {{Fe}{in}{media}} \right\rbrack_{Compound} - \left\lbrack {{Fe}{}{in}{media}} \right\rbrack_{{No}{Compound}}} \right)}{\left\lbrack {{Fe}{in}{media}} \right\rbrack_{{No}{Compound}}} \times 100}$

Representative data is provided in Table 13 where the % Fe efflux for the specified compounds of the invention lie in the following ranges: A<30%, B 30-100%, C 100-150%; D>150%.

TABLE 13 Fe efflux data for Selected Compounds Fe- Fe- Fe- Compound Efflux Compound Efflux Compound Efflux 1 D 31 B  55 B 2 C 32 C  56 B 3 D 33 D  57 C 4 B 39 D  58 A 6 A 40 D  61 B 7 B 42 D  91 B 8 C 47 B 101 A 9 B 48 D 117 A 10  B 49 D 122 A 15  D 50 A 138 A 23  D 52 B 147 A 171   A 172  C 178 C 

The invention claimed is:
 1. A compound of formula (Ib):

wherein X is O; R₁ is selected from:

R₆ and R₇ are independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, CN, CO₂R₉ and N(R₉)₂; or R₆ and R₇ taken together with the atoms to which they are attached form an unsubstituted 6 membered aryl or heteroaryl ring; each R₈ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, halo, (CH₂)_(m)CO₂R₉ and (CH₂)_(m)N(R₉)₂; each R₉ is independently selected from C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl; R₂ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, C₃₋₈ cycloalkyl and

or R₁ and R₂ taken together form

wherein V is CH₂, O or S and R₁₁ and R₁₂ are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, halo, C₁₋₆haloalkyl, (CH₂)_(m)C₃₋₈cycloalkyl, (CH₂)_(m)aryl, (CH₂)_(m)heterocyclyl, (CH₂)_(m)heteroaryl and COR₁₃ where R₁₃ is selected from OH, OC₁₋₆alkyl, OC₂₋₆alkenyl, OC₂₋₆alkynyl and N(R₉)₂, wherein the cycloalkyl, heterocycloalkyl or heteroaryl ring of the bicyclic structure formed by R₁ and R₂ may be optionally substituted by one or more first substituents selected from the group consisting of C₁₋₆alkyl, C₂₋₆alkenyl, oxo (═O), —OH, C₁₋₆alkylO—, C₂₋₆alkenylO—, —CO₂H, —CO₂C₁₋₆alkyl, —OC(═O) C₁₋₆alkyl, —NH₂, —NH(C₁₋₆alkyl), —N(C₁₋₆alkyl)₂, —C₁₋₆alkylNH₂, —C₁₋₆alkylNH(C₁₋₆alkyl), —C₁₋₆alkylN(C₁₋₆alkyl)₂, —OC₁₋₆alkylNH₂, —OC₁₋₆alkylNH(C₁₋₆alkyl), —OC₁₋₆alkylN(C₁₋₆alkyl)₂, —CN, -halogen, —CF₃, —OCF₃, —CHF₂, —OCHF₂, heterocyclyl, heteroaryl, —OC₁₋₆alkylheterocyclyl, and —C(═O)C₁₋₆alkyl, or R₁ and R₂ are both:

R₃ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C(R₁₀)₂)_(m)CO₂R₉; R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl and C₁₋₆haloalkyl; and R₅ is hydrogen, (C(R₁₀)₂)_(m)aryl, (C(R₁₀)₂)_(m)heteroaryl or O(C(R₁₀)₂)_(m)heteroaryl wherein the aryl and heteroaryl are optionally substituted by one or more second substituents selected from the group consisting of C₁₋₆alkyl, C₂₋₆alkenyl, oxo (═O), —OH, C₁₋₆alkylO—, C₂₋₆alkenylO—, —CO₂H, —CO₂C₁₋₆alkyl, —OC(═O) C₁₋₆alkyl, —NH₂, —NH(C₁₋₆alkyl), —N(C₁₋₆alkyl)₂, —C₁₋₆alkylNH₂, —C₁₋₆alkylNH(C₁₋₆alkyl), —C₁₋₆alkylN(C₁₋₆alkyl)₂, —OC₁₋₆alkylNH₂, —OC₁₋₆alkylNH(C₁₋₆alkyl), —OC₁₋₆alkylN(C₁₋₆alkyl)₂, —CN, -halogen, —CF₃, —OCF₃, —CHF₂, —OCHF₂, heterocyclyl, heteroaryl, —OC₁₋₆alkylheterocyclyl, and —C(═O)C₁₋₆alkyl; or R_(4a) is CN and R₄ and R₅ are both hydrogen or taken together form:

where R₁₄ is hydrogen, (C(R₁₀)₂)_(m)aryl or (C(R₁₀)₂)_(m)heteroaryl wherein the aryl and heteroaryl are optionally substituted by one or more third substituents selected from the group consisting of C₁₋₆alkyl, C₂₋₆alkenyl, oxo (═O), —OH, C₁₋₆alkylO—, C₂₋₆alkenylO—, —CO₂H, —CO₂C₁₋₆alkyl, —OC(═O) C₁₋₆alkyl, —NH₂, —NH(C₁₋₆alkyl), —N(C₁₋₆alkyl)₂, —C₁₋₆alkylNH₂, —C₁₋₆alkylNH(C₁₋₆alkyl), —C₁₋₆alkylN(C₁₋₆alkyl)₂, —OC₁₋₆alkylNH₂, —OC₁₋₆alkylNH(C₁₋₆alkyl), —OC₁₋₆alkylN(C₁₋₆alkyl)₂, —CN, -halogen, —CF₃, —OCF₃, —CHF₂, —OCHF₂, heterocyclyl, heteroaryl, —OC₁₋₆alkylheterocyclyl, and —C(═O)C₁₋₆alkyl; or R_(4a) is absent and R₄ and R₅ taken together form an aryl or heteroaryl group, said aryl or heteroaryl being monocyclic or bicyclic, and wherein the aryl or heteroaryl is optionally substituted by one or more fourth substituents selected from the group consisting of C₁₋₆alkyl, C₂₋₆alkenyl, oxo (═O), —OH, C₁₋₆alkylO—, C₂₋₆alkenylO—, —CO₂H, —CO₂C₁₋₆alkyl, —OC(═O) C₁₋₆alkyl, —NH₂, —NH(C₁₋₆alkyl), —N(C₁₋₆alkyl)₂, —C₁₋₆alkylNH₂, —C₁₋₆alkylNH(C₁₋₆alkyl), —C₁₋₆alkylN(C₁₋₆alkyl)₂, —OC₁₋₆alkylNH₂, —OC₁₋₆alkylNH(C₁₋₆alkyl), —OC₁₋₆alkylN(C₁₋₆alkyl)₂, —CN, -halogen, —CF₃, —OCF₃, —CHF₂, —OCHF₂, heterocyclyl, heteroaryl, —OC₁₋₆alkylheterocyclyl, and —C(═O)C₁₋₆alkyl; each R₁₀ is independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, hydroxy, C₁₋₆alkoxy, C₁₋₆haloalkyl, C₁₋₆haloalkoxy, CN, halo and N(R₉)₂; m is 0 or an integer of 1 to 6; or a pharmaceutically acceptable salt thereof.
 2. The compound according to claim 1 wherein one or both of the following applies: i) R₁ is selected from the group consisting of:

or a pharmaceutically acceptable salt thereof; and ii) R₂ is selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₃₋₈cycloalkyl.
 3. The compound according to claim 1 wherein one of the following applies: i) R₁ and R₂ are both

or a pharmaceutically acceptable salt thereof; or ii) R₁ and R₂ together are selected from:

wherein V is CH₂ or O and R₁₁ and R₁₂ are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, (CH₂)_(m)C₃₋₈cycloalkyl, (CH₂)_(m)aryl, (CH₂)_(m)heterocyclyl, (CH₂)_(m)heteroaryl and COR₁₃ where R₁₃ is selected from OH, OC₁₋₆alkyl, OC₂₋₆alkenyl, OC₂₋₆alkynyl and N(R₉)₂, or a pharmaceutically acceptable salt thereof.
 4. The compound according to claim 1 wherein R₃ is selected from hydrogen, C₁₋₆alkyl, CH₂CO₂H and CH₂CO₂CH₃ or a pharmaceutically acceptable salt thereof.
 5. The compound according to claim 1 wherein R₄ and R_(4a) are each independently selected from hydrogen, C₁₋₃alkyl, C₂₋₃alkenyl, C₂₋₃alkynyl and C₁₋₃haloalkyl; and R₅ is hydrogen, (CH₂)_(m)aryl or (CH₂)_(m)heteroaryl wherein the aryl and heteroaryl are optionally substituted by the one or more second substituents selected from the group consisting of C₁₋₆alkyl, C₂₋₆alkenyl, oxo (═O), —OH, C₁₋₆alkylO—, C₂₋₆alkenylO—, —CO₂H, —CO₂C₁₋₆alkyl, —OC(═O) C₁₋₆alkyl, —NH₂, —NH(C₁₋₆alkyl), —N(C₁₋₆alkyl)₂, —C₁₋₆alkylNH₂, —C₁₋₆alkylNH(C₁₋₆alkyl), —C₁₋₆alkylN(C₁₋₆alkyl)₂, —OC₁₋₆alkylNH₂, —OC₁₋₆alkylNH(C₁₋₆alkyl), —OC₁₋₆alkylN(C₁₋₆alkyl)₂, —CN, -halogen, —CF₃, —OCF₃, —CHF₂, —OCHF₂, heterocyclyl, heteroaryl, —OC₁₋₆alkylheterocyclyl, and —C(═O)C₁₋₆alkyl, or a pharmaceutically acceptable salt thereof.
 6. The compound according to claim 1 wherein R_(4a) is absent and R₄ and R₅ taken together form an aryl or heteroaryl group, said aryl or heteroaryl being monocyclic or bicyclic, and wherein the aryl or heteroaryl is optionally substituted by the one or more fourth substituents selected from the group consisting of C₁₋₆alkyl, C₂₋₆alkenyl, oxo (═O), —OH, C₁₋₆alkylO—, C₂₋₆alkenylO—, —CO₂H, —CO₂C₁₋₆alkyl, —OC(═O) C₁₋₆alkyl, —NH₂, —NH(C₁₋₆alkyl), —N(C₁₋₆alkyl)₂, —C₁₋₆alkylNH₂, —C₁₋₆alkylNH(C₁₋₆alkyl), —C₁₋₆alkylN(C₁₋₆alkyl)₂, —OC₁₋₆alkylNH₂, —OC₁₋₆alkylNH(C₁₋₆alkyl), —OC₁₋₆alkylN(C₁₋₆alkyl)₂, —CN, -halogen, —CF₃, —OCF₃, —CHF₂, —OCHF₂, heterocyclyl, heteroaryl, —OC₁₋₆alkylheterocyclyl, and —C(═O)C₁₋₆alkyl, or a pharmaceutically acceptable salt thereof.
 7. The compound according to claim 6 wherein R₄ and R₅ taken together form a phenyl ring, a 2-pyridinyl ring, 3-pyridinyl ring, 4-pyridinyl ring, 3-pyridazinyl ring, 4-pyridazinyl ring, 2-furanyl, 3-furanyl, 2-thiophenyl ring, 3-thiophenyl ring, 2-thiazolyl ring, 3-thiazolyl ring, 4-thiazolyl ring, 3-isoxazolyl ring, 4-isoxazolyl ring, 5-isoxazolyl ring, 4-(1,2,3-thiadiazolyl) ring, 5-(1,2,3-thiadiazolyl) ring, 4-thiadiazolyl ring, 5-thiadiazolyl ring, 2-benzo[b]thiophenyl, 3-benzothiophenyl ring, 3-(1H)-indolyl ring or a 4H-thieno[3,2-c]chromene ring, or a pharmaceutically acceptable salt thereof.
 8. The compound according to claim 1 wherein one of the following applies: i) R_(4a) is CN and R₄ and R₅ taken together form:

where R₁₄ is hydrogen, (C(R₁₀)₂)_(m)aryl or (C(R₁₀)₂)_(m)heteroaryl wherein the aryl and heteroaryl are optionally substituted by the one or more third substituents selected from the group consisting of C₁₋₆alkyl, C₂₋₆alkenyl, oxo (═O), —OH, C₁₋₆alkylO—, C₂₋₆alkenylO—, —CO₂H, —CO₂C₁₋₆alkyl, —OC(═O) C₁₋₆alkyl, —NH₂, —NH(C₁₋₆alkyl), —N(C₁₋₆alkyl)₂, —C₁₋₆alkylNH₂, —C₁₋₆alkylNH(C₁₋₆alkyl), —C₁₋₆alkylN(C₁₋₆alkyl)₂, —OC₁₋₆alkylNH₂, —OC₁₋₆alkylNH(C₁₋₆alkyl), —OC₁₋₆alkylN(C₁₋₆alkyl)₂, —CN, -halogen, —CF₃, —OCF₃, —CHF₂, —OCHF₂, heterocyclyl, heteroaryl, —OC₁₋₆alkylheterocyclyl, and —C(═O)C₁₋₆alkyl, or a pharmaceutically acceptable salt thereof; or ii) R_(4a) is CN and R₄ and R₅ are both hydrogen.
 9. A compound according to claim 1 which is a compound of formula (II):

wherein X, R₃, R₄, R_(4a) and R₅ are as defined in claim 1, R₁₁ and R₁₂ are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, C₁₋₆haloalkyl, halo, (CH₂)_(m)C₃₋₈cycloalkyl, (CH₂)_(m)aryl, (CH₂)_(m)heterocyclyl, (CH₂)_(m)heteroaryl and COR₁₃ where R₁₃ is selected from OH, OC₁₋₆alkyl, OC₂₋₆alkenyl, OC₂₋₆alkynyl and N(R₉)₂ and r is 1, 2 or 3, or a pharmaceutically acceptable salt thereof.
 10. A compound according to claim 9 which is a compound of formula (IIa):

wherein R₃, R₄, R_(4a), R₅, R₁₁ and R₁₂ are as defined for formula(II), or a pharmaceutically acceptable salt thereof.
 11. A compound according to claim 9 which is a compound of formula (IIb):

wherein R₃, R₄, R_(4a), R₅, R₁₁ and R₁₂ are as defined for formula(II), or a pharmaceutically acceptable salt thereof.
 12. A compound according to claim 9 which is a compound of formula (IIc):

wherein R₃, R₄, R_(4a), R₅, R₁₁ and R₁₂ are as defined for formula(II), or a pharmaceutically acceptable salt thereof.
 13. A compound according to claim 1 which is a compound of formula (IIIa):

wherein R₂, R₃, R₄, R_(4a), R₅, R₆, R₇ and R₈ are as defined in claim 1, or a pharmaceutically acceptable salt thereof.
 14. The compound according to claim 1 which is a compound of formula (IIId):

wherein R₃, R₄, R_(4a) and R₅ are as defined in claim 1, or a pharmaceutically acceptable salt thereof.
 15. A compound according to claim 1 which is a compound of formula (V):

wherein X, R₂, R₃, R₄, R_(4a) and R₅ are as defined in claim 1, or a pharmaceutically acceptable salt thereof.
 16. A compound according to claim 1, which is a compound of formula (VI):

wherein X, V, R₃, R₄, R_(4a) and R₅ are as defined for formula (Ib), R₁₁ and R₁₂ are each independently selected from hydrogen, C₁₋₆alkyl, C₂₋₆alkenyl, C₂₋₆alkynyl, halo, C₁₋₆haloalkyl, (CH₂)_(m)C₃₋₆ cycloalkyl, (CH₂)_(m)aryl, (CH₂)_(m)heterocyclyl, (CH₂)_(m)heteroaryl and COR₁₃ where R₁₃ is selected from OH, OC₁₋₆alkyl, OC₂₋₆alkenyl, OC₂₋₆alkynyl and N(R₉)₂ and s is 0, 1 or 2, or a pharmaceutically acceptable salt thereof.
 17. A compound according to claim 16, which is a compound of formula (VIb):

wherein R₃, R₄, R_(4a), R₅, R₁₁ and R₁₂ are as defined for formula(VI), or a pharmaceutically acceptable salt thereof.
 18. A compound according to claim 1, which is any one of the following compounds: (E)-N′-(6,7-Dihydroquinolin-8(5H)-ylidene)nicotinohydrazide; (E)-N′-(5H-Cyclopenta[b]pyridin-7(6H)-ylidene)-3,4-dimethoxybenzohydrazide; (E)-N′-(6,7-Dihydroquinolin-8(5H)-ylidene)-2-(2-(pyrrolidin-1-yl)ethoxy) benzohydrazide hydrochloride; (E)-4-Methyl-N′-(1-(pyrimidin-2-yl)propylidene)-1,2,3-thiadiazole-5-carbohydrazide; (Z)—N′-(Imidazo[1,2-a]pyridin-2-ylmethylene)-3-methoxybenzohydrazide; (2E,N′E)-2-Cyano-N′-(6,7-dihydroquinolin-8(5H)-ylidene)-3-(2-hydroxyphenyl) acrylohydrazide; (E)-N′-(2,3-dihydro-4H-pyrano[3,2-b]pyridin-4-ylidene)nicotinohydrazide; N′-(bis(6-Methylpyridin-2-yl)methylene)-4-hydroxy-3-methoxybenzohydrazide; 5-chloro-N′-(di(pyridin-2-yl)methylene)-3-((dimethylamino)methyl)-2-hydroxybenzohydrazide;

or a pharmaceutically acceptable salt thereof.
 19. A pharmaceutical composition comprising a compound according to claim 1 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier. 